The NC Clean Energy Technology Center, in a collaboration with Meister Consultants Group, reports all but four states took some form of solar policy action on policies or rates in 2015. As you might imagine, a number of policy considerations for solar involved net metering.
Regarding the issue of solar electricity, the report has issued these details:
27 states considered or enacted changes to net metering policies
24 states formally examined or resolved to examine some element of the value of distributed generation
7 states had policy action on community solar