You get 1 point per mile flown in full fare Y-class (which is often more expensive than discount biz), 1.25 points for every biz mile flown and 1.50 points for every 1st class mile flown.

If I recall correctly then biz RTW fare is "D" but I could be mistaken. Why not check topics on this forum back in May/June this year when there was a lot of talk about RTW 100K runs and all fare classes were covered quite thoroughly.