how many served in the 20th century?
9
col : # | name | birth and death | office started | office ended row 1 : 1 | geir vídalín | 27 october 1761\n–\n20 september 1823 | 1801 | 1823 row 2 : 2 | steingrímur jónsson |  | 1824 | 1845 row 3 : 3 | helgi thordersen | 8 april 1794\n–\n4 december 1867 | 1846 | 1866 row 4 : 4 | 'pétur pétursson | 3 october 1808\n–\n15 may 1891 | 1866 | 1889 row 5 : 5 | hallgrímur sveinsson | 5 april 1841\n–\n16 december 1909 | 1889 | 1908 row 6 : 6 | þórhallur bjarnarson | 2 december 1855\n–\n15 december 1916 | 1908 | 1916 row 7 : 7 | jón helgason | 1866\n–\n1942 | 1917 | 1939 row 8 : 8 | sigurgeir sigurðsson | 3 august 1890\n-\n13 october 1953 | 1939 | 1953 row 9 : 9 | ásmundur guðmundsson | 6 october 1888\nreykholt\n–\ | 1954 | 1989 row 10 : 10 | sigurbjörn einarsson | 30 june 1911\nvestur-skaftafel | 1959 | 1981 row 11 : 11 | pétur sigurgeirsson\n(son of sigur | 2 june 1919\n–\n3 june 2010 | 1981 | 1989 row 12 : 12 | ólafur skúlason | 29 december 1929\n–\n9 june 2008 | 1989 | 1997 row 13 : 13 | karl sigurbjörnsson\n(son of sigurb | 5 february 1947\nreykjavík | 1998 | 2012 row 14 : 14 | agnes sigurðardóttir | 19 october 1954\nísafjörður | 24 june 2012 | incumbent
how many served in the 20th century?
# Name Birth and death Office started Office ended
1 Geir Vídalín 27 October 1761\n–\n20 September 1823 1801 1823
2 Steingrímur Jónsson 1824 1845
3 Helgi Thordersen 8 April 1794\n–\n4 December 1867 1846 1866
4 'Pétur Pétursson 3 October 1808\n–\n15 May 1891 1866 1889
5 Hallgrímur Sveinsson 5 April 1841\n–\n16 December 1909 1889 1908
6 Þórhallur Bjarnarson 2 December 1855\n–\n15 December 1916 1908 1916
7 Jón Helgason 1866\n–\n1942 1917 1939
8 Sigurgeir Sigurðsson 3 August 1890\n-\n13 October 1953 1939 1953
9 Ásmundur Guðmundsson 6 October 1888\nReykholt\n–\n29 May 1969\nReykjavík 1954 1989
10 Sigurbjörn Einarsson 30 June 1911\nVestur-Skaftafellssýsla\n–\n28 August 2008\nReykjavík 1959 1981
11 Pétur Sigurgeirsson\n(son of Sigurgeir Sigurðsson, 8th Bishop of Iceland) 2 June 1919\n–\n3 June 2010 1981 1989
12 Ólafur Skúlason 29 December 1929\n–\n9 June 2008 1989 1997
13 Karl Sigurbjörnsson\n(son of Sigurbjörn Einarsson, 10th Bishop of Iceland) 5 February 1947\nReykjavík 1998 2012
14 Agnes Sigurðardóttir 19 October 1954\nÍsafjörður 24 June 2012 Incumbent
9