How many non-immigrant visas does the United States grant in Mexico per year?

In the year ending September 2007, the U.S embassy in Mexico processed applications for 1,300,000 non-immigrant visas (visitor, student, temporary work, and other categories) according to this page on the site of the U.S Embassy in Mexico. This year the embassy is projecting more than 1,600,000 applications – and projections are generally overtaken by actual applications, as the graph at the bottom of this page shows.
I called the Embassy myself this week to find out how many of the 1,300,000 non-immigrant visas processed last year were actually granted, but was told that information is not available. Then I emailed a press and information officer at the Department of Home Security and was directed to this page.
According to THAT info, not including border passes, a total of 1,027,737 non-immigrant visas were issued from Mexico last year. That would suggest that only 272,263 non-immigrant visa applications DIDN’T get granted by the US Embassy in Mexico, if their figures are anything to go by. Can that be right? Was Juan just one of the unlucky few?
Or is my maths just wrong?

Figures provided by the U.S Department of State