Statistics can be tricky things.
As soon as I had updated The Database, I began to wonder, how successful is the [long-time refuted]Jerome Gambit?
It didn't seem right to just ask ChessBase 8 to search for the starting position of the Jerome Gambit (1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.Bxf7+) in The Database and see how well White did – after all, in my research I was collecting published games (and including games sent to me) and those tend to favor wins by White.
(Still, I checked: White scored 44% overall in the main line in The Database.)
So, I decided instead to just look at the FICS (Free Internet Chess Service) games, as I have been collecting them, en masse, and have almost all of the Jerome Gambit games played there since 1999.
Of 6,764 FICS games, White won 2,700 and drew 186, for a score of 41%.
The numbers for the Italian Four Knights Jerome Gambit, 1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Nc3 Bc5 5.Bxf7+, (there is some overlap with the main line Jerome) are 1,528 FICS games, with White winning 554 and drawing 34, for a score of 37%.
As anyone who has played the Blackburne Shilling Jerome Gambit (1.e4 e5 2.Nf3 Nc6 3.Bc4 Ne4 4.Bxf7+) might suspect, the line is more robust for White; of 3,378 FICS games, White has 1,822 wins and 80 draws, scoring 55%.
Of course, as they say, "your mileage may vary". Keep practicing. (My scores are 80%, 78% and 90%. Bill Wall's are at least 96%, 90% and 100%.)