SEOUL, March 28 (Xinhua) -- South Korea's working-age population was expected to drop from next year, indicating a so-called demographic cliff coming closer, statistical office data showed Thursday.

According to Statistics Office's estimate for the country's demographic change from 2017 to 2067, the working-age population, or those aged 15-64, began to fall after peaking at 37.57 million in 2017.

The workforce was forecast to decline by an annual average of 330,000 from 2020 when the country's baby boomers, born from 1955 to 1963, enters the stage of old age.

In the 2030s, the annual average reduction of the working-age population was estimated at 520,000.

The rapid fall estimate bolstered worry about the demographic cliff, which refers to a sudden drop in the heads of household, eventually leading to a consumption cliff.

The ratio of the working-age population to the total population was estimated to tumble from 73.2 percent in 2017 to 49.9 percent in 2056 and 45.4 percent in 2067 respectively.