15 August 1947 to 27 May 1964 (16 years, 286 days)
27 May 1964 to 9 June 1964 (13 days)
9 June 1964 to 11 January 1966 (1 year, 216 days)
11 January 1966 to 24 January 1966 (13 days)
24 January 1966 to 24 March 1977 (11 years, 59 days)
24 March 1977 to 28 July 1979 (2 years, 126 days)
28 July 1979 to 14 January 1980 (170 days)
14 January 1980 to 31 October 1984 (4 years, 291 days)
31 October 1984 to 2 December 1989 (5 years, 32 days)
2 December 1989 to 10 November 1990 (343 days)
10 November 1990 to 21 June 1991 (223 days)
21 June 1991 to 16 May 1996 (4 years, 330 days)
16 May 1996 to 1 June 1996 (16 days)
1 June 1996 to 21 April 1997 (324 days)
21 April 1997 to 19 March 1998 (332 days)
19 March 1998 to 22 May 2004 (6 years, 64 days)
22 May 2004 to 26 May 2014 (10 years, 4 days)
26 May 2014 - Incumbent