http://www.lynchhummer.com/ for everything you needed to know about the H1 including year to year changes.

1995 was the first year that a Hummer was offered from the factory with a gas engine. The gas engine is significantly quieter than the diesel and offered a reliable addition to the Hummer line. The disadvantages to the gas engine included lower fuel economy and decreased fording ability. 1995 was the highest production for the H1 with approximately 1,432 built, about 25 -30% of which were gas models.