About 10 years ago it was practically non-existent. It started with a few wider sidewalks in the city center getting painted over and dubbed "bike paths". Just for example, you can look at these pics here for some of the most prolific cases. Most of these have already been abandoned by the town council.

About 5 years ago the council stated they wanted more people to start cycling so they spent some actual money and built up a few new bike paths. Most are still on the sidewalks (with a few notable exceptions), but some have a concrete surface. The problem is that they face the very serious problem of being disconnected from each other, as well as each of them being interrupted by other infrastructure. For example, you are riding along the bike path and are finally getting to put in some speed. Then you notice a bigger intersection ahead of you where the bike path leads you directly to the underpass, where you are supposed to dismount for about 50 meters. Then you have to climb up to street level and start up again, until the next junction comes up.

There are also other weird cases, such as having a two-way bike lane on one side of the road. As soon as you get to the end of it, you find yourself in the wrong way of street traffic with all your options at that point being to go on wrong way cycling, cross the six-lane road to reach your proper lane, or, step on the sidewalk and push your bike till the next intersection.

Since a lot of these bike paths are quite rough, it's probably not strange that many people would prefer a solid MTB in order to commute here.