I think they meant that 40% of people would be subject to it if they don't have health insurance. The other 60% either don't make enough income or have some other circumstance that makes them exempt.
Yes but that is 40% of the currently uninsured are subject to it, which means it is like 10% overall. So apparently the CBO is estimating 9 out of 10 of them will buy insurance and the rest will pay the penalty.
Bottom line is that all the people screaming about this "tax" are likely already covered and therefore not subject to the mandate or the penalty. The new myth that is being perpetuated is that everyone is going to have to pay some new tax in 2014.