2/Technically the 1st  difficulty adj. took place on 01/27/09 at block 2016 - Adjustment:0%, Estimated Hashrate:4.21MH/s, Avg Block TIme:17 mins

But it was the 20th ajd that took place on 02/14/10 at block 40,320 that introduced 1st  dif increase- Adjustment:+100%,..