Recent data on the nation's population trends show that the country's population has declined for the fourth straight year, while the average population age has risen.

The Ministry of Interior and Safety released its annual statistics yearbook on Tuesday, showing that the registered population stood at 51-million-325-thousand-329 as of the end of last year, a decrease of zero-point-22 percent from the previous year.

However, despite the population decline, the number of households has increased due to the rise in single-person households, with those in their 60s and 70s accounting for 38-point-one percent of the total.

The average age has increased by zero-point-six years to 44-point-eight years from the previous survey, reflecting the country's growing aging society.

The average age of all men stood at 43-point-seven years, while the average age for all women was 45-point-nine years.