The decline in full-year gross domestic product outpaced the 6.2 percent fall during Mexico's currency and debt crisis in 1995.
A bright spot was a 1.2 percent expansion in the fourth quarter of 2009 from the third quarter, although the level of economic output was 3 percent lower than the same period of 2008, the report said.
Still, it was the second consecutive quarter of GDP growth. The economy expanded 2.9 percent in the third quarter.
The report represented something of a comeback from the steep 10.3 percent decline in the second quarter, and officials had previously estimated a full-year 2009 contraction of around 7 percent.
The Treasury Department said it expects GDP to grow about 3 percent for all of this year, while noting "the recent evolution of the economy suggest the probability that growth may be greater than that prediction is considerable."
It said the country lost 181,271 formally registered jobs in 2009. Many of Mexico's 107 million people work in the informal sector.
