I couldn't give you numbers, but here in the US a dismal number likely couldn't make it through either text... followed by a larger, possibly more dismal block that could make it through the text, but could take it only in the context of - and thus constitute confirmation of - their political side/tribe.
I'd say that, together, the twain would constitute a solid 80% of the population.
I almost typed a bigger number evenly divisible by 10, but the rush of fear that ensued backed me down to 80%....
I just think about how infrequently we're out and about, and a conversation occurs that isn't either "Yay for our team!" or "What kind of a fucking imbecile are you?", i.e. how rarely conversations break out in which both parties are willing to genuinely allow inputs new to them, explore logical conclusions, genuinely debate, playfully/cleverly admit bias/errors and - GASP! - attempt to rise above them in public....
Let's just say it seems utterly hopeless.
Then again, we live in a part of the country traditionally considered "about as dumbfuck as it gets", so maybe I'm almost panicking in vain....