Most Senior SF Writer

Who, among the major writers, has been writing for the longest time? And who held the record before them?

Started writing	Died	Who?	Span	Years on Top
1851	1905	Jules Verne	54	54
1879	1930	Arthur Conan Doyle	51	25
1888	1946	H. G. Wells	58	16
1912	1950	Edgar Rice Burroughs	38	4
1919	1975	Murray Leinster	56	25
1928	2006	Jack Williamson	78	31
1937	2013	Fred Pohl	68	7
1949	still alive	James Gunn		6+

Interestingly, Jack Williamson had the longest run (ignoring Verne since we did not look for writers older than him.)