South Korea reported the first natural decline in population last year as the number of deaths outpaced that of newborns amid the country’s rapid aging and chronic low birth rate, data showed Wednesday. The number of newborns came to a record low of 272,400 last year, down 10 percent, or 30,300, from a year earlier, according to preliminary data provided by the Statistics Korea. Last year, an all-time high of 305,100 people died, up 3.4 percent, or 10,000, from the previous year. This resulted in a decline of 33,000 in the country’s population. The number of deaths topped that of newborns here in what’s called a “dead cross” phenomenon for the first time since 1970, when the statistics agency began compiling related data. This means the country’s population will naturally decline.