The number of preschooers and students in elementary, middle and high schools in South Korea declined for a sixth straight year in 2011 due mainly to the nation's declining birthrate, a report showed Wednesday. According to the report released by the Ministry of Education, Science and Technology, the number of students below college level totaled 7.6 million as of April this year, down about 220,000, or 2.8 percent, from a year earlier. This marked the steepest drop in a decade. The post-Korean War baby boom drove the number of students to hover around 10 million in 1980, but it has since reversed to a downward trend except for some fluctuations during the mid 2000s. The decline is largely attributed to a decrease in the number of marriages, a ministry official said. South Korea's fertility rate, or the number of babies that a woman is expected to have during her lifetime, amounts to 1.22 in 2010, the lowest among countries in the Organization for Economic Cooperation and Development (OECD), according to government data. The number of elementary school students fell 5.1 percent to stand at 3.13 million this year. The 2011 tally came to slightly more than half the total from a generation ago, the data showed. The number of middle school students fell 3.3 percent to 1.91 million, while that of high schoolers edged down 0.9 percent to 1.94 million, according to the data. Kindergartners were the exception with the total number advancing 4.9 percent from a year earlier to 565,034 in 2011. "The number of high school graduates is expected to retreat about 30 percent in a decade, another telltale sign of a fast-aging society." the ministry official said.