Decile 10 (richest): ~48%
Decile 9: ~15%
Decile 8: ~10%
Decile 7: ~8%
Decile 6: ~6%
Deciles 1 through 5 combined: ~12%, so about 1 to 3% each
I wouldn't necessarily focus on it, but it's something good for your mental model of how to solve the challenge.
The reason I say I wouldn't focus on it is I'm coming around to the idea that "carbon footprint" is effectively a marketing campaign brought on by oil companies to have us focus our individual power where it has the lowest leverage - sorting trash, our own individual emissions, etc, Instead of mobilizing hundreds, thousands, millions, and billions of people to change policy and technology.
Sources like this: www.oxfam.org.uk/media/press-releases/richest-1-emit-as-much-planet-heating-pollution-as-two-thirds-of-humanity-oxfam/