Here are tables for tax as a slice of GDP and tax rates by income level.
In terms of GDP, the last two years seem to be outliers, probably due to the economy tanking. The rest of the decade went from 8.0 to 10.2, pretty much exactly in line with the rest of the last 30 years.
The table of tax rates by income level is much more striking: the poorest 20% saw their taxes cut nearly in half since 1980, while the richest 20% saw only about 10% reduction in tax burden. So basically, the tax system got a whole lot more progressive in the last 30 years. (Progressive = the more you make, the higher your tax rate.) That's interesting in context of the stuff I've been seeing from the left lately about how we need to raise taxes on the rich, since it appears the burden has been shifting that way already for the last few decades.