Authorities have investigated more than 15,000 civil servants involved in 13,000 cases of commercial bribery over the last five years, according to an official statement issued on Wednesday.

Government officials have faced extra scrutiny in a national crackdown on commercial bribery, according to a statement on the website of the Ministry of Supervision.

From November 2007 to June 2012, judicial and law enforcement authorities probed more than 81,000 commercial bribery cases involving a total of 22.2 billion yuan (about 3.6 billion U.S. dollars), the statement said.

The crackdown has helped rebuild market credit and correct the practice of building businesses through gift-giving, the statement said.