Government officials and outside experts say that several other governments, including those of Russia, Israel and France, also conduct cyber-espionage but not at the scale attempted by China.

“It’s not China alone. Dozens of other countries are involved,” said Shawn Henry, former head of cybersecurity investigations for the FBI who is president of CrowdStrike Services, a cybersecurity company.

The volume of Chinese cyber-intrusions has made identifying them easier because tactics tend to be similar among certain hacking crews, with telltale sections of code sometimes appearing across different pieces of malicious software.

The Verizon report identified 44 million compromised records from 621 confirmed data breaches in 2012, of which 19 percent were the results of government-affiliated espionage. Retail institutions were the most common victims of data breaches, with profit-minded hackers most often based in Romania, the United States, Bulgaria or Russia.