This article is from the The Monster Truck FAQ, by Jeff Hawkins with numerous contributions by others.
A. There are currently 14 trucks in the BIGFOOT fleet alone. You can see a
list of these trucks along with their specifications in the Team BIGFOOT
Section of the Bigfoot home page:
Around the world there are over 500 monster trucks, only 100 or so of
which are full blown racing trucks. Others are exhibition, car crushers,
ride trucks, or promotions vehicles. This includes the majority in the
US. There are several in Canada, England, Australia, and New Zealand.