As miles go, that's not a lot: Its not a lot of car riding saved, and from a hardcore cyclist's perspective its not much when such a person will do a 100 mile "Century" recreational ride in a day.
But I suggest that it is an important milestone for three reasons: (1) it is a lot more mileage than I have put on in the last two years or so; (2) it represents a sea change to my own mindset regarding car riding and (3) it is an example of what can be accomplished if you start simple and slow.
Last year, I did about 500 miles on the year. The year before only about 300 -- a mere six or seven miles, average, of a weekend running errands.
And that is the point of my third point: Having mentally red tagged the car years ago, I started slow. Driving a bike for local weekend errands, quick mid-week runs to the store, or to breakfast out or to the to park with the kids on weekends. ( See Red Tag Your Car, Part I, Part II and Part III)
As the weekend trips improved my skills, comfort level and physical stamina, I began to ride more to work during the week. Now, I ride most every day that I do not have to deliver my son to school near his mother's house 25 miles away. And in the summer the car I use for those errands is parked so much we sometimes start it to keep the battery up.
At this time (see item #2) I tend to view the need to ride in a car as a failure; of errand route planning, of ability to find a truly local option, of trying to squeeze too much to fast into a life on the road.
As for the mileage, if you don't bike much now it seems like a lot. I promise that the longest stretch I ever rode to get that mileage was across town in Pasadena, California -- five miles at best. I work 1.80 miles from where I live; my daughter's preschool is 1 mile away; we shop 1.98 miles in the other direction, next to my other daughter's school and my employer's main office. One reason I am able to accumulate these miles two and three miles at a time is we have largely resolved one of the major "would-buts" of non-automobility: Live where you want to work and play.
You can do this too. It's easy. It's green. It's even healthy for you!