Pretty incredible that the second slowest winning time was before World War II.
YEAR FINAL WINNING TIME
1936 3:51.2
1944 3:47.8 WR
1948 3:49.8
1952 3:45.2
1956 3:41.2
1960 3:35 WR
1964 3:38.8
1968 3:34.91
1972 3:36.3
1976 3:39.65
1980 3:38.4
1984 3:32.53 OR
1988 3:35.96
1992 3:40.12
1996 3:35.78
2000 3:32.07 OR
2004 3:34.19
2008 3:33.11
2012 3:34.08
2016 3:50.00