I'm not sure if "wheelchair accessible" and "accessible with a double stroller" fall in the same category. If they do, then Sweden is pretty wheelchair accessible.
There are some significant differences. For example, strollers can get up a step, and you can potentially take the little passenger out and carry them and their stroller over uneven ground or up a set of steps. In a wheelchair, you don't have those kinds of options, so the availability of alternative access via ramps and lifts (elevators) is much more important.