Just based on what I've seen on the internet, it appears that EE women and Slavic women have incredible hair with thick healthy ends that reach ridiculous lengths- knee and beyond. Their hair is superemely healthy from end to end with minimal taper even past knee length.

I see super long hair from other countries and it's no where near as good. For example, a lot of the super long haired women from China have horrendous volume even past waist, with really bad ends. Indian women also have some great hair genetics however, but seem to lag behind the EEs.