The chart on page three of your link shows the US at an effective rate of 27.1% versus the remainder of the OECD at an effective rate of 23.3%. It also shows marginal differences of up to 6%. It's only when we "weight" the other nations' rates to "indicate their relative importance" that we look better. This is the same shit that drives NASA to show global warming by changing temperatures measured far in the past - the idea that we can simply manipulate numbers to make ourselves look better.
On what basis do you believe the nonpartisan, non policy prescriptive Congressional Research Service is doing this in order to 'make the US look better'? This is just another example of dismissing inconvenient information.
Regardless of what you think, it shows that the US rate is most certainly not 39%.