I'm a bit confused about the number achieving the different levels of uprades. There seem to be a lot of people who have achieved Tier 7 without achieving the lower tiers. And for the Easy level more have achieved Tier 5 than Tier 4. Please can someone explain?

Fifty-Fifty: Easy

Tier 1 - score 1400 in an easy game (423 players)
Tier 2 - score 1405 in an easy game (197 players)
Tier 3 - score 1410 in an easy game (151 players)
Tier 4 - score 1415 in an easy game (111 players)
Tier 5 - score 1420 in an easy game (131 players)
Tier 6 - score 1425 in an easy game (99 players)
Tier 7 - score 1430 in an easy game (285 players)

Fifty-Fifty: Intermediate

Tier 1 - score 1250 in an intermediate game (729 players)
Tier 2 - score 1275 in an intermediate game (359 players)
Tier 3 - score 1300 in an intermediate game (290 players)
Tier 4 - score 1325 in an intermediate game (241 players)
Tier 5 - score 1350 in an intermediate game (239 players)
Tier 6 - score 1375 in an intermediate game (230 players)
Tier 7 - score 1400 in an intermediate game (275 players)

I suspect those numbers indicate the number of players currently at that level, so as players move up they are only listed once, not once at every level.

Ah yes, that makes sense, thanks!