from back in 2008 "the Petroleum Equipment Institute, a trade group, found that there were at least 170 static electricity fires at gas stations from 1992 to 2006. Considering that the American Petroleum Institute estimates that there are 11 billion refuelings in the United States a year, the problem probably isn’t a big one." from https://www.nytimes.com/2008/07/27/automobiles/27STATIC.html

I'll note that in the state I live (MN) it's technically illegal to get back in your car while pumping (you have to be " in close attendance to the dispenser nozzle").