what time period had no shirt sponsor?
1982-1985
col : year | kit manufacturer | shirt sponsor | back of shirt sponsor | short sponsor row 1 : 1977–1978 |  | national express |  |  row 2 : 1982–1985 | umbro |  |  |  row 3 : 1985–1986 | umbro | whitbread |  |  row 4 : 1986–1988 | henson | duraflex |  |  row 5 : 1988–1989 |  | gulf oil |  |  row 6 : 1991–1993 | technik | gulf oil |  |  row 7 : 1993–1994 | club sport | gulf oil |  |  row 8 : 1994–1995 | klūb sport | empress |  |  row 9 : 1995–1996 | matchwinner | empress |  |  row 10 : 1996–1997 | uk | endsleigh insurance |  |  row 11 : 1997–1999 | errea | endsleigh insurance |  |  row 12 : 1999–2004 | errea | towergate insurance |  |  row 13 : 2004–2008 | errea | bence building merchants |  |  row 14 : 2008– | errea | mira showers |  |  row 15 : 2009–2011 | errea | mira showers | psu technology group |  row 16 : 2011–2013 | errea | mira showers | barr stadia | gloucestershire echo row 17 : 2013– | errea | mira showers | gloucestershire college | gloucestershire echo
what time period had no shirt sponsor?
Year Kit Manufacturer Shirt Sponsor Back of Shirt Sponsor Short Sponsor
1977–1978 National Express
1982–1985 Umbro
1985–1986 Umbro Whitbread
1986–1988 Henson Duraflex
1988–1989 Gulf Oil
1991–1993 Technik Gulf Oil
1993–1994 Club Sport Gulf Oil
1994–1995 Klūb Sport Empress
1995–1996 Matchwinner Empress
1996–1997 UK Endsleigh Insurance
1997–1999 Errea Endsleigh Insurance
1999–2004 Errea Towergate Insurance
2004–2008 Errea Bence Building Merchants
2008– Errea Mira Showers
2009–2011 Errea Mira Showers PSU Technology Group
2011–2013 Errea Mira Showers Barr Stadia Gloucestershire Echo
2013– Errea Mira Showers Gloucestershire College Gloucestershire Echo
1982-1985