EIA updated its country profile for Mexico, noting the oil sector accounted for 13 percent of the country's export earnings last year.
Mexico is one of the top 10 oil-producing countries in the world, with an estimated 10 billion barrels of proven reserves as of 2013.
EIA said Mexico produced an average 2.5 million barrels of crude oil per day, a level that's more than 20 percent less than its peak from 2004-09.
"Notably, crude oil production in 2013 was at its lowest since 1995 and continues to decline thus far in 2014," it said in its Thursday report.
EIA said the decline in oil production was having a direct impact on the health of Mexico's economy, a situation exacerbated by a declining export market.
EIA said that, despite Mexico's status as a crude oil exporter, its economy is still heavily dependent on imported petroleum products. Last year, the country was a net importer of petroleum products and relied on the United States for 44 percent of its motor gasoline.