About 80 percent of mobile phone users worldwide have received spam, according to a study of consumers and mobile operators released Wednesday.

That's bad news for mobile operators because most of the users who have received mobile spam blame the operators, according to the study. More specifically, the study found that users are more likely to change operators than mobile phone numbers to fight mobile spam.

The study was conducted jointly by the University of St. Gallen in Switzerland and Intrado, a vendor of emergency communications services. It also was conducted with cooperation from the International Telecommunication Union (ITU). The survey was based on responses from 1659 mobile users and 154 wireless operators.

Both consumers and operators expect mobile spam to become a bigger problem in the future. About 83 percent of respondents from the telecommunications industry expect mobile spam to become a critical issue within the next two years.

Consumers and the industry also agreed that self-regulation by mobile operators was the best way to fight spam. The study found that operators are in what it called "a trial and error" phase in terms of experimenting with solutions to mobile spam.

The trade group for GSM operators said the survey pinpointed a number of key issues.

"Whilst there is no single solution to the mobile spam problem, there are a number of key components to any real solution, including identifying the spammers by rejecting anonymous or spoofed access and making them pay through clear and suitable charging mechanisms," Tom Phillips, the group's government & regulatory affairs officer, said in a statement.