According to research from anti-spam firm Sophos, 56 per cent of unwanted emails comes from the US.
After the US, the study showed that spam comes from a wide spread of countries. Canada sent out 6.6 per cent of spam, while China and South Korea followed.
A spokesperson from Sophos said that the widespread problem highlights the trouble with anti-spam laws.
Sophos said that many computers producing spam appeared to be controlled by hackers in Eastern Europe.