An anti-graft watchdog says the Philippine government was cheated of $3.85 billion in tax revenues in 2011, part of massive illicit money flows that totaled more than $400 billion in the past five decades.

Global Financial Integrity said in a report Tuesday that illicit financial outflows including proceeds from crime, corruption and tax evasion totaled $132.9 billion in a 52 year period from 1960.

Another $277.6 billion illegally entered the country, predominantly through false invoicing of imports to evade tariffs.

It says the government has lost at least $23 billion in revenue from customs evasion since 1990 and lost an average of $1.46 billion in tax revenue each year since 2000.

The report estimates that the underground economy was equal to nearly 30 percent of GDP in 2011.