For the past 2 or 3 years I've averaged about 4,000. My mother averages around 750 miles a year. Obviously a family of homebodies.
i can't imagine, it varies so much. even month-to-month. hell, even weekly. over the winter i was doing about 3,000 miles a month. it's dropped off since then, but it's still pretty high. i'm a homebody too, this is almost all work related.
About 6k miles per year for the past couple of years but likely <4k miles in 2012. Our usual thing puts 20-30 miles per week on the clock so I often use fuel stabilizer to keep the gasoline from going stale in the tank and plugging up the fuel injectors.
for the past decade and more: zero. for the first decade of my life, not even my parents did. he worked for the railroad and we went everywhere on his pass. my third decades were the only time i did any serious amounts of driving. (it was only in the 70s, come to think of it, that i even had a vehicle for any apreacable amont of it) maybe 40, 50, or even 60,000 miles many of those years. i liked to explore every back road i could find. and generally only owned vehicules that were capable of doing so. my fourth decade i didn't own any, and my fifth i owned one for only i think two or at most four years of it. made maybe a dozen respectably longish trips with it. not cross country but across and up and down the northern part of the state of california, and again back into portions of nevada and oregon. so i don't know, i'll let someone else do the math. when i owened one i drove it into the ground, untill it colapsed into a little pile of rust to be shoveled off the side of the road. no major accidents, just literally drove the poor things to death. that and half the time i couldn't really afford to keep up maintainence on them. one of the several reasons for my not having owned one a greater percentage of my life.
more miles than i'd like to admit to but as i came to driving later in life rather than earlier then i guess it would average out over my lifetime as very few every year.