Afghans paid nearly $1bn (£658m) in bribes last year, according to a new survey that reveals that corruption in the country has doubled since 2007.
The study by the monitoring group Integrity Watch Afghanistan showed that the average value of bribes paid in 2009 was $156. The average per capita income is $502 per year.
Almost a third of civil servants said they have been forced to pay a bribe to obtain a public service, while 13% of households said that they had paid bribes to secure their own sources of income
The survey also showed that more than half the country's population feels that corruption is helping the Taliban's expansion.
Equally worrying for Nato forces combating the insurgency is the finding that the judiciary and the police were identified as the two most corrupt institutions in Afghanistan.
While most respondents said they hoped that state institutions would tackle the problem of corruption, there was an increasing tendency to turn to non-state actors to solve their problems, a trend that could further bolster support for the insurgency.
"Corruption is weakening the legitimacy of the state," said Lorenzo Delesgues, a founder and co-director of IWA.
The survey sampled 6,498 people in 32 of Afghanistan's 34 provinces over November and December 2009.
More than a quarter of Afghans (26%) felt deprived of access to justice and security because of corruption. Half (50%) of those surveyed said that corruption within the state was helping expansion of the Taliban either absolutely (36%) or a little (14%).
Weak law enforcement was identified as a major cause for corruption with as many as 28% of civil servants saying they had to pay bribes to secure or retain their jobs. However donor money was also identified as a major cause of corruption
President Hamid Karzai – criticised regularly by the international community for his apparent unwillingness to tackle graft – was seen as the best bet for countering corruption (80% identified the presidency as the best institution to deal with the problem), though more than half the people said he had not performed on this issue.