Joe DiMaggio played only 13 seasons: 1936-1942, 1946-1951. His tenure largely coincided with that of heavyweight boxing champion Joe Louis, both born in 1914.
The file with supporting data in recent posts now has an annual breakdown of DiMaggio's home runs, home and road. Click this link and look at tab "DiMaggio by Year", which also contains a graph.
In only two seasons did DiMaggio have a better AB/HR at home than road: 1940 and 1951. Shockingly, in SEVEN seasons DiMaggio had single digit home run totals at home, including his injury plagued 1949 season (5). Four times he hit only 8 at home and twice only 9.
Four times DiMaggio hit at least 20 homers on the road: 27, 24, 23, 21. DiMaggio's best at home was 19, which coincided with his road best of 27 for a total of 46 and DiMaggio's best AB/HR (13.5). Next best was 15.2 in 1948, the only other season DiMaggio led AL in home runs (39).
In DiMaggio's rookie season he needed 19.4 more AB to homer at home than on the road. DiMaggio had other high differences: 17.1, 14.7, 14.6. For his career DiMaggio needed 6.45 more AB to homer at home than on the road. That's 39.7% more AB needed to homer at home. Almost 40%.
In his ten World Series (51 games, 199 AB) DiMaggio hit all 8 of his homers on the road:
2 - Polo Grounds New York
1 - Wrigley Field Chicago
1 - Crosley Field Cincinnati
3 - Ebbets Field Brooklyn
1 - Shibe Park Philadelphia
In addition to Yankee Stadium, the only other park in which DiMaggio played a World Series game and failed to homer was Sportsman's Park III St. Louis: two games
DiMaggio hit his final home run on October 8, 1951 at the Polo Grounds during the World Series: Yanks led the Giants 2-1 in the fifth and DiMaggio hit a two run homer off 23 game winner Sal Maglie with Yogi Berra on first base. Yanks won the game 6-2, tieing the series 2-2. Yanks won in six games.
DiMaggio's 56 game hitting streak went from May 15 through July 16, 1941. On June 18, 1941 54,487 saw Joe Louis defeat Billy Conn at the Polo Grounds. The rematch was June 19, 1946 ... at Yankee Stadium where Louis fought 12 times.