Number Systems of the World by Complexity

This is cool, but the Finnish system seems like it should be higher.

Yksi, kaksi, ... kahdeksan, yhdeksan, kymmenen

(diacritics etc. omitted because I'm lazy)

It looks as though the symmetricality between yksi, kaksi/kahdeksan yhdeksan implies a "two less than ten, one less than ten" pattern rather than an "8, 9" pattern. Can anyone comment on the etymology of kahdeksan/yhdeksan?

Well done, very interesting work.