This year I commuted as much as I could by bike, generally 2-3 times a week. I don't know how many miles were commuting as my ride log includes both commuting and my road bike riding. In any case, due to my training last winter indoors I found I was always pushing myself during the commute as if I were on the road bike. The only things that kept me from commuting were the weather and after work events. My alternate commute is on the NYC subway and that's just been horrendous lately so I tried to avoid it as much as possible.
I'm doing the same training indoors this winter as last so I'll come out as fast and strong as ever.