Most Senior SF Writer

Who, among the major writers, has been writing for the longest time? Today it is Fred Pohl, but before him?

Started writing	Died	Who?	Years on Top
1851	1905	Jules Verne	54
1879	1930	Arthur Conan Doyle	25
1888	1946	H.G. Wells	16
1912	1950	Edgar Rice Burroughs	4
1919	1975	Murray Leinster	25
1928	2006	Jack Williamson	31
1937	still alive	Fred Pohl	5+

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