For every five marriages civil affairs authorities in China registered last year, they registered one divorce, according to a report released by the Ministry of Civil Affairs on Thursday.

The report says that 24.24 million people in the country tied the knot in 2009 and there were 2.47 million registered divorces, an increase of 8.8 percent on the previous year.

The report also suggests the crude divorce rate - the number of divorces per 1,000 population - was about 1.85/1,000 on the Chinese mainland in 2009, compared with 1.71/1,000 in 2008.

"In truth, the divorce rate has kept increasing over the past decades as the country has witnessed its economic growth. It is almost a side effect," said Tang Jun, a social development and policy researcher with the Chinese Academy of Social Sciences.

According to official statistics the figure was almost 0.4/1000 in 1985, he said.

As the first generation of the only child family planning policy born during the 1980s enters marriageable age, the divorce rate is likely to soar in coming years, he said.

"They are better educated than their parents, are more independent economically and have developed a stronger sense of self, which tends to wreck marriages more easily," he said.

Citing a regional survey conducted by his team, he said that extramarital affairs have become a rising cause of divorce in the country, particularly in large cities. Rural women had better tolerance of extramarital affairs compared with their city counterparts, he said.

A rising divorce rate, however, does not indicate that the Chinese have become less enthusiastic about marriage, he said. The latest report shows that more than 24 million people tied the knot last year, 2.28 million more than 2008.

Notably, those older than 40 accounted for more than 12 percent of the total newlyweds in 2009, up nearly 2 percent on the previous year, according to the report.

"Most of them had a previously failed marriage, but it shows that the Chinese are becoming more open about remarriage," Tang said.

People aged between 20 and 24 accounted for only 37 percent of the marriages last year, down 10 percent compared with 2005.

According to the ministry, that indicated more people in China were marrying later, as encouraged by the family planning department since the late 1970s.

Tang said a faster pace of life and work pressure, especially in urban areas, also contributed to people marrying at a later age.