Don't have the actual raw data, so calculations are just
estimates. It shows that 20% of Top
Income Earners make 60% of Total Income, while 80% of Middle and Low Income Earners make 40%
of Total Income.
Apologies for the information overload. 
Assumptions:
1) Total taxpayers are only 731,348, while CPF Board shows
1,324,368 active members. Therefore the difference between the two
figures are assumed to be the low income earners, who make less
than $20,000 a year and shown in IRAS's statement as zero (under
IRAS's below $20,000 row and Resident column).
2) MOM claims that there are 2,341,900, but on checking the
Department of Statistics website population
statistics, there are around 2.3 million males and females
ranging from ages 20-60. I cannot reconcile the difference between
CPF Board's 1.3 million and MOM's 2.3 million. Are there 1 million
self-employed (CPF Board does not take into account self-employed),
housewives, early retirees and handicapped around? Self-employed equals taxi drivers and hawkers? If
it's true, then it will increase the high income earners percentage
very very substantially.


Source: IRAS

Source: CPF Board

