MDG Anti-corruption protests in Brazil — Young people demonstrate against government waste and corruption in Niteroi, Brazil in June 2013. Photograph: Yasuyoshi Chiba/AFP/Getty Images

2013 global corruption barometer – get the data

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More than half of people believe the level of corruption in their countries has increased over the past two years, according to Transparency International

More than half of people believe the level of corruption in their countries has increased over the past two years, according to the world's largest public opinion survey on the subject.

The 2013 global corruption barometer, released on Tuesday by NGO Transparency International, surveyed 114,270 people in 107 countries. Unlike the better-known corruption perceptions index, which relies on expert opinion, this project surveys the public on their views and experiences of corruption.

More than one in four respondents (27%) said they paid a bribe over the past 12 months when accessing key public institutions and services. Of those who reported paying a bribe, 40% said they did so "to speed things up"; 27% said "it was the only way to obtain a service", while 21% said they paid a bribe "as a gift, or to express gratitude". The remaining 12% of respondents said it was "to get a cheaper service".

Corruption is, by definition, difficult to measure. Transparency International's surveys are among the few sources of data on the subject, though they focus largely on perception. Now in its eighth edition, this year's survey is the largest of its kind and includes some countries, such as Libya and Tunisia, for the first time.

Other key findings from the survey:

• Political parties are considered the most corrupt institution, followed by the police and the judiciary. Globally, religious institutions are seen as least corrupt. In Israel, Japan, Sudan and South Sudan, however, religious bodies were seen to be highly corrupt.

• Nearly two-thirds of respondents said they believe personal contacts and relationships help get things done in the public sector in their country. In 10 countries, including Israel, Italy, Malawi, Russia and Vanuatu, this figure was more than 80%.

• In 2008, 31% of respondents said their government's efforts to fight corruption were effective. This year that figure fell to 22%.

• In the UK, the media and political parties were rated most corrupt and 5% of people surveyed reported paying a bribe.

• Wealthier respondents reported paying bribes more often than their poorer counterparts. Of those with income above their country's average, 31% said they paid a bribe last year, compared with 26% of respondents with below average income.

• Globally, 28% of men reported paying a bribe, compared with 25% of women. In some countries, such as Nepal and Pakistan, many more men reported paying bribes than women. In Colombia, meanwhile, 27% of women reported paying bribes compared with only 16% of men.

Public anger at corruption perceived or uncovered has exploded in recent years, with street protests and citizens' initiatives such as I Paid a Bribe multiplying worldwide. More than half of those surveyed by Transparency International said they would be willing to speak up and report an incident of corruption.

In a report presenting the survey's findings, the NGO argues corruption not only increases the cost of essential services borne by individuals and the public purse, but that perceptions of widespread graft erode essential trust and faith in the democratic and legal process.

"Corruption can, and often does, infringe on fundamental rights. For those surviving on less than $2 a day … the additional cost of bribery can mean trade-offs are made between health and hunger, between school entrance fees and the shoes necessary to wear to school," argues the report, adding: "Bribery not only costs the individual paying the bribe – it also undermines the efficient and equitable allocation of resources, people's respect for the rule of law and the overall integrity of a society."

Corruption has shot up the development agenda in recent years. In the UK, tackling corruption is a key plank of prime minister David Cameron's "golden thread". Some have called for goals and targets on good governance to be included in whatever framework succeeds the millennium development goals, which expire in 2015. The impact of corruption on development, however, remains a subject of debate, as does the level of attention it should receive from aid donors.

"If we're talking about where the world ought to focus its aid energy for the next 15 years, I simply wouldn't use corruption in the same sentence (or even paragraph) as civil war or property rights," argued Columbia University political scientist Chris Blattman in November, pointing to dozens of studies that have failed to find evidence that corruption has an impact on economic growth.