A picture is worth a thousand words, no?
(Updated) By the way, 2008 was an Olympic year. Tennis was played from August 10 to August 17.
Yes, your eyes are correct. In 2008, the ITF did not any conduct any out-of-competition (OOC) tests in 5 out of 12 months. However, the underlying story is much worse...
First, as seen in the table below, 79.1 percent of OOC tests took place between September and December. Yes, that would be after the US Open AND after the Olympics. No OOC tests were conducted in January, prior to the Australian Open. Only 9 tests (8.2% of the total) were conducted prior to Roland Garros and Wimbledon. The remaining 12.7% percent of tests occurred in July following Wimbledon. Zero OOC tests occurred in August, leading up to the US Open and the Olympics.
If you go even deeper into the data, to the days when the tests occurred, the story is worse. All 110 OOC missions were crammed into a grand total of 33 days. And there was only 1 OOC mission conducted (March 1) between January 1 and April 24 (i.e., there was virtually no OOC testing for the first 4 months of the year).
I don't remember reading anything about this (or hearing anything on XM radio) when these statistics were released, do you?
Data Source: ITF
Update: ESPN's Howard Bryant has written a piece on PEDs. He touches on Ryan Braun, Spain, but also discusses Nadal and tennis: "In any other universe, even though he has never been linked to performance enhancers and has never failed a drug test, Nadal and tennis would be at the center of the doping question."