(Recasts with effect of drop in oil revenue)
MEXICO CITY, March 2 (Reuters) - The Mexican government's income wilted in January, as oil revenues plunged with the decline in oil prices, and the country's fiscal deficit ballooned from a year earlier, the Finance Ministry said on Monday.
Mexico had a fiscal deficit of 91.5 billion pesos ($6.1 billion) in January, compared with 4.9 billion pesos in January of last year, the Finance Ministry said in a statement.
Tax revenue rose during the month but total income fell 3.4 percent, dragged down by a 43.5 percent drop in oil revenue as oil production fell, the ministry said. Mexico relies on oil sales to fund about one-third of the federal budget.
Oil output in January fell 6.5 percent compared with the same month last year, the ministry said, adding that prices for Mexican crude averaged $52.40 per barrel compared with $91.80 in January 2014 and below the $79 per-barrel price used to calculate the 2015 budget.
In late January, the Finance Ministry cut its 2015 spending plan by an amount equivalent to 0.7 percent of gross domestic product. Flagging oil output has pushed some economists to expect further budget cuts this year. ($1 = 15.0100 Mexican pesos) (Reporting by Jean Luis Arce; Editing by Leslie Adler)