Brazil\'s primary budget surplus significantly dropped for the first five months of 2013, worsening the worry that the government would most likely fall short of its annual target of fiscal savings, the Central Bank said on Friday. The primary surplus was 46.7 billion Brazilian reais (some 21 billion U.S. dollars), or 2.45 percent of the Gross Domestic Product (GDP), down 26 percent compared with the same period of last year, the bank said in a report. The primary budget balance, which represents the public sector\'s excess revenue over expenditures before interest payments on the debt, is a gauge closely watched by investors as it measures a country\'s ability to service its debt. From January to May, the payment of the public debt\'s interests was 100.4 billion reais (some 45.1 billion dollars), resulting in a nominal deficit of 53.7 billion reais (some 24.1 billion dollars), or 2.82 percent of GDP, the report added. The data aggravated the prospect that the government would fail to meet its target of fiscal savings for the whole year. The government had set 155.9 billion reais (about 70 billion dollars) as its primary surplus target for 2013, equivalent to 3.1 percent of the GDP, but last week Finance Minister Guido Mantega lowered it to 2.3 percent, compared with 2.38 percent in 2012.