You can get the FIDE rating list here. I used R statistical software to analyse the data for the latest OTB rating list (of 15th Sep. 2014). At the moment there are 383543 active FIDE players. Among them, slightly less than one third (107320 players) are rated.
As noted by others, the FIDE rating floor is 1000:
"Players whose ratings drop below 1000 are listed on the next list as ‘delisted’. Thereafter, they are treated in the same manner as any other unrated player." (FIDE Rating Regulations effective from 1 July 2014, article 7.21).
From that I understand that players going below 1000 Elo are unrated at all effects. However, the list shows 14 people with a rating of 0 (I do not know what this means, though).
For rated players, please see the figure below. It shows the number of FIDE active rated players for different Elo intervals: 1000-1100, 1100-1200, etc. So, to answer your last three bullets, as of 15th Sep. 2014:
- there are 31603 players with Elo higher than 2000, or 8.2% of the
- there are 10220 players with Elo higher than 2200, or 2.7% of
- there are 768 players with Elo higher than 2500, or 0.2% of