These days I don't bother putting the Garmin on the bike for recreational riding, I use it only for HR when I'm actually training, as opposed to just riding around. As a result I no longer have any accurate idea of annual mileages. I do use it when on tour, though, largely because some acquaintances like me to upload the route data so they can see where I've been.
It's been a pretty modest year by my usual standards, I've probably averaged less than eight hours a week on the bike. So, what, 6000 miles or so? Just a guess.