MEXICO CITY, Sept 11 (Reuters) - Mexico's proven oil reserves are 0.4 percent higher in 2013 than they were a year earlier, according to a new field-by-field estimate from the country's hydrocarbons commission.
Proven reserves total 10.07 billion barrels of oil equivalent (boe), up from 10.03 billion boe last year, the commission said on Wednesday.
Mexico's state oil monopoly Pemex calculates oil reserves slightly higher at 10.12 billion boe for 2013.
Reserves have remained relatively unchanged since 2009, but Pemex's lack of investment in exploration over many years has led to a precipitous decline in the country's reserve base. Mexico boasted proven crude oil reserves of about 55 billion barrels in 1990 but this has fallen by more than 80 percent.
More than three-quarters of Mexico's oil and gas resources, however, are made up of prospective, or yet to be certified, oil and gas deposits, according to Pemex data. Those resources include nearly 30 billion boe in the country's territorial deep waters of the Gulf of Mexico.
Mexico has the biggest proven oil reserves in Latin America after Venezuela and Brazil.
Last month, President Enrique Pena Nieto proposed an overhaul of the energy sector aimed at luring private investment into the sector by creating a new scheme of profit-sharing contracts. The Mexican Congress has yet to take action on the proposal.