Is it possible that you would consider any story that isn't about a white heterosexual man one of those? I'm really wondering, because I could see myself keeping a running tally like this once I thought I noticed a trend–kinda like noticing how they put pumpkin into everything in the fall.
But of course, 80% is actually pretty close to the number of Americans that are not white heterosexual men. We may just have gotten used to an overrepresentation in movies, politics, and our social life.
I don't think there's much of an overrepresentation - I haven't heard a human interest piece on a rural/conservative person on there that didn't deal with the opioid crisis in the last 6 months - and I listen every day. I look back to where I grew up which was a much more conservative rural area and frequently think about how I'd never feel like any of the stories on NPR would apply to me.
But of course, 80% is actually pretty close to the number of Americans that are not white heterosexual men. We may just have gotten used to an overrepresentation in movies, politics, and our social life.