That 15% sounds about right, which would mean just about half of the Democratic Party are progressives.
Wrongo Pero! That 15% includes all progressive independents as well. Folks like me, and Chunkstyle. As does the 25% liberal number. Democrats are mostly centrists labeled liberals. Don't be putting me among the Dems just because I vote for them.
Perhaps 15% of our elected officials are progressive...? I kinda doubt it.
If half of the Democratic Party was progressive Bernie would be President right now.
Proof's in the pudding...the old Centrist from Delaware sits the Resolute Desk.