How common is it for cats to fart?

I only ask this because last night while I was petting my little kitty (he is a real little jerk) he let out a HUGE fart like a real machine gunner! Anyways, I have had this cat for about 5 or 6 years and have never heard a peep out of him except when he is cranky or hungry. But this was a first and it was a real bang. I also have a dog who has none stop horrible flatulence so I was surprised when my cat jumped on the band wagon. I know it is a little silly but there is nothing stranger or more hilarious than to hear a little kitty cat let out a ripping fart!