what is the number of tournaments played on grass?
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col : week | start date | type | tournament | surface | town | country | continent | prize money row 1 : 35 | october 24 | premier wta tour\nchampionships | sony ericsson championships - istanbul 2011 | hard | istanbul | turkey | europe | $4,550,000 row 2 : 8 | march 7 | premier mandatory | bnp paribas open | hard | indian wells | united states | north america | $4,500,000 row 3 : 9 | march 21 | premier mandatory | sony ericsson open | hard | key biscayne | united states | north america | $4,500,000 row 4 : 13 | may 2 | premier mandatory | mutua madrileña madrid open | clay | madrid | spain | europe | $4,500,000 row 5 : 32 | october 3 | premier mandatory | china open | hard | beijing | china | asia | $4,500,000 row 6 : 26 | august 15 | premier 5 | western & southern financial group women's open | hard | cincinnati | united states | north america | $2,000,000 row 7 : 31 | september 26 | premier 5 | toray pan pacific open | hard | tokyo | japan | asia | $2,000,000 row 8 : 10 | april 4 | premier 700 | family circle cup | clay | charleston | united states | north america | $700,000 row 9 : 11 | april 18 | premier 700 | porsche tennis grand prix | clay (i) | stuttgart | germany | europe | $700,000 row 10 : 23 | july 25 | premier 700 | bank of the west classic | hard | stanford | united states | north america | $700,000 row 11 : 24 | august 1 | premier 700 | mercury insurance open | hard | san diego | united states | north america | $700,000 row 12 : 2 | january 10 | premier 600 | medibank international sydney | hard | sydney | australia | oceania | $600,000 row 13 : 15 | may 16 | premier 600 | brussels open | clay | brussels | belgium | europe | $618,000 row 14 : 18 | june 13 | premier 600 | aegon international | grass | eastbourne | united kingdom | europe | $600,000 row 15 : 27 | august 22 | premier 600 | new haven open at yale | hard | new haven | united states | north america | $600,000 row 16 : 34 | october 17 | premier 600 | kremlin cup | hard (i) | moscow | russia | europe | $1,000,000 row 17 : 36 | october 31 | international wta\ntour championships | commonwealth bank tournament of champions | hard (i) | sofia | bulgaria | europe | $750,000 row 18 : 1 | january 1 | international | shenzhen open | hard | shenzhen | china | asia | $500,000 row 19 : 1 | january 3 | international | brisbane international | hard | brisbane | australia | oceania | $220,000 row 20 : 6 | february 21 | international | abierto mexicano telcel presentado por | clay | acapulco | mexico | north america | $220,000 row 21 : 7 | february 28 | international | malaysian open 2011 | hard | kuala lumpur | malaysia | asia | $220,000 row 22 : 10 | april 4 | international | andalucia tennis experience | clay | marbella | spain | europe | $220,000 row 23 : 11 | april 18 | international | grand prix de sar la princesse lalla meryem | clay | fes | morocco | africa | $220,000 row 24 : 12 | april 25 | international | barcelona ladies open | clay | barcelona | spain | europe | $220,000 row 25 : 15 | may 16 | international | internationaux de strasbourg | clay | strasbourg | france | europe | $220,000 row 26 : 17 | june 6 | international | e-boks sony ericsson open | hard | copenhagen | denmark | europe | $220,000 row 27 : 17 | june 6 | international | aegon classic | grass | birmingham | united kingdom | europe | $220,000 row 28 : 18 | june 13 | international | unicef open | grass | 's-hertogenbosch | netherlands | europe | $220,000 row 29 : 20 | july 4 | international | collector swedish open women | clay | båstad | sweden | europe | $220,000 row 30 : 20 | july 7 | international | bucharest open | clay | bucharest | romania | europe | $250,000
what is the number of tournaments played on grass?
Week Start Date Type Tournament Surface Town Country Continent Prize Money
35 October 24 Premier WTA Tour\nChampionships Sony Ericsson Championships - Istanbul 2011 Hard Istanbul Turkey Europe $4,550,000
8 March 7 Premier Mandatory BNP Paribas Open Hard Indian Wells United States North America $4,500,000
9 March 21 Premier Mandatory Sony Ericsson Open Hard Key Biscayne United States North America $4,500,000
13 May 2 Premier Mandatory Mutua Madrileña Madrid Open Clay Madrid Spain Europe $4,500,000
32 October 3 Premier Mandatory China Open Hard Beijing China Asia $4,500,000
5 February 14 Premier 5 Dubai Duty Free Tennis Championships Hard Dubai United Arab Emirates Asia $2,000,000
6 February 21 Premier 5 Qatar Ladies Open Hard Doha Qatar Asia $2,168,400
14 May 9 Premier 5 Internazionali BNL d'Italia Clay Rome Italy Europe $2,000,000
25 August 8 Premier 5 Rogers Cup presented by National Bank Hard Montreal Canada North America $2,000,000
26 August 15 Premier 5 Western & Southern Financial Group Women's Open Hard Cincinnati United States North America $2,000,000
31 September 26 Premier 5 Toray Pan Pacific Open Hard Tokyo Japan Asia $2,000,000
4 February 7 Premier 700 OPEN GDF Suez Hard (I) Paris France Europe $700,000
10 April 4 Premier 700 Family Circle Cup Clay Charleston United States North America $700,000
11 April 18 Premier 700 Porsche Tennis Grand Prix Clay (I) Stuttgart Germany Europe $700,000
23 July 25 Premier 700 Bank of the West Classic Hard Stanford United States North America $700,000
24 August 1 Premier 700 Mercury Insurance Open Hard San Diego United States North America $700,000
2 January 10 Premier 600 Medibank International Sydney Hard Sydney Australia Oceania $600,000
15 May 16 Premier 600 Brussels Open Clay Brussels Belgium Europe $618,000
18 June 13 Premier 600 Aegon International Grass Eastbourne United Kingdom Europe $600,000
27 August 22 Premier 600 New Haven Open at Yale Hard New Haven United States North America $600,000
34 October 17 Premier 600 Kremlin Cup Hard (I) Moscow Russia Europe $1,000,000
36 October 31 International WTA\nTour Championships Commonwealth Bank Tournament of Champions Hard (I) Sofia Bulgaria Europe $750,000
1 January 1 International Shenzhen Open Hard Shenzhen China Asia $500,000
1 January 3 International Brisbane International Hard Brisbane Australia Oceania $220,000
1 January 3 International ASB Classic Hard Auckland New Zealand Oceania $220,000
2 January 10 International Moorilla Hobart International Hard Hobart Australia Oceania $220,000
4 February 7 International PTT Pattaya Open Hard Pattaya City Thailand Asia $220,000
5 February 14 International Memphis International Hard (I) Memphis United States North America $220,000
5 February 14 International XIX COPA BBVA COLSANITAS Clay Bogotá Colombia South America $220,000
6 February 21 International Abierto Mexicano TELCEL presentado por HSBC Clay Acapulco Mexico North America $220,000
7 February 28 International Malaysian Open 2011 Hard Kuala Lumpur Malaysia Asia $220,000
7 February 28 International Monterrey Open Hard Monterrey Mexico North America $220,000
10 April 4 International Andalucia Tennis Experience Clay Marbella Spain Europe $220,000
11 April 18 International Grand Prix De SAR La Princesse Lalla Meryem Clay Fes Morocco Africa $220,000
12 April 25 International Barcelona Ladies Open Clay Barcelona Spain Europe $220,000
12 April 25 International Estoril Open Clay Estoril Portugal Europe $220,000
15 May 16 International Internationaux de Strasbourg Clay Strasbourg France Europe $220,000
17 June 6 International e-Boks Sony Ericsson Open Hard Copenhagen Denmark Europe $220,000
17 June 6 International Aegon Classic Grass Birmingham United Kingdom Europe $220,000
18 June 13 International UNICEF Open Grass 's-Hertogenbosch Netherlands Europe $220,000
20 July 4 International Collector Swedish Open Women Clay Båstad Sweden Europe $220,000
20 July 7 International Bucharest Open Clay Bucharest Romania Europe $250,000
21 July 11 International Internazionali Femminili di Palermo Clay Palermo Italy Europe $220,000
21 July 11 International NURNBERGER Gastien Ladies Clay Bad Gastein Austria Europe $220,000
22 July 18 International Banka Koper Slovenia Open Hard Portorož Slovenia Europe $220,000
23 July 25 International Mid-Atlantic Women's Tennis Championships Hard Washington, D.C. United States North America $220,000
29 September 12 International Bell Challenge Hard (I) Quebec City Canada North America $220,000
29 September 12 International Tashkent Open Hard Tashkent Uzbekistan Asia $220,000
30 September 19 International Guangzhou International Women's Open Hard Guangzhou China Asia $220,000
30 September 19 International Hansol Korea Open Hard Seoul South Korea Asia $220,000
33 October 10 International Generali Ladies Linz Hard (I) Linz Austria Europe $220,000
33 October 10 International HP Japan Women's Open Tennis 2011 Hard Osaka Japan Asia $220,000
34 October 17 International BGL BNP PARIBAS Luxembourg Open Hard (I) Luxembourg Luxembourg Europe $220,000
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