It was not close to zero before 2007. For quite a long time, Minneapolis has a solid set of bike paths and a good bicycle culture to accompany it - all along the Mississippi river, around the numerous lakes in the city, and also the Midtown Greenway, an off-grade rail trail that runs all the way from the river to the lakes, which opened in 2000. In addition to several other bicycle commuter paths that predate this change.
These new bike lanes were the city doubling down on being a bicycle-friendly city.
I didn't see any mention of starting numbers, at least not in the summary/abstract. I believe Minneapolis has been bike-friendly for quite some time, so the starting point was probably not zero.
