That´s the statistics of car usage in S2. It however doesnt accurately show the cars popularity at the moment. The fo8 has so many laps cause it was the main oval car before patch U, bf1 hasnt got so many laps cause it was added later and hasn´t been around that long. But it does show which cars are more popular in general.
formula xr 6,914,738 laps
formula v8 6,712,884 laps
fz50 gtr 3,567,678 laps
bmw sauber 2,746,218 laps
fxo gtr 2,335,366 laps
xf gtr 2,176,806 laps
uf1000 2,168,240 laps
xf gti 1,464,379 laps
xr gtr 1,070,563 laps
mrt5 1,035,939 laps
rb4 1,000,206 laps
fxo 971,457 laps
xr gt turbo 817,643 laps
uf gtr 731,403 laps
fz50 394,642 laps
lx4 391,851 laps
lx6 354,081 laps
ra 281,261 laps
xr gt 274,988 laps