Keep in mind these are median amounts first of all. This is very middle person on the CFA spectrum. Second of all these are for CFA Charterholders, that would be, the majority of the individuals would have 3 yrs, now it's 4 yrs of experience is now required. Experience, however is a relative term, especially as the CFA institute guages it, in terms of teh spectrum of jobs that qualify under that banner. I.e. if you are doing research for an investment bank or if you are an associate portfolio manager, that is better experience than if you are a trading assistant for a broker or doing simple trade reconciliation for a trading firm, but these do count for experience. I do know two people who have passed all 3 levels and who are working just as investmnet representatives for a discount brokerage in their call centre. This isn't a bad job, but it's not what you think of people, who would pass all three levels would do; it's definatly under what they are capable of doing.
Also if you read the actual survey the amount made for a CFA charterholder with more XP is more important. The more experience a charterholder has the more money they make and the increase is impressive.