What pot do you have? Boil off rate is directly proportional to the surface area of the wort, so proportional to the diameter of your pot.
I boil off about 1.5 gallons in 60 minutes in a pot with a 13.5" diameter. If you are anywhere close to the same diameter, then you may be measuring incorrectly....
Primary #1 - Midnight Ryeder (Midnight Wheat and Rye)
Primary #2 - Florida Weiss
Primary #3 - Kane-DOH APA (Honey Citra APA)
Secondary #1 - Downtown Flanders Brown (brewed August 2012)
Keg #1 - Raspberry Florida Weiss
Keg #2 - Cinnamon Raisin Cider
Keg #3 - NONE!
Bottled - NONE!