BRUSSELS, June 13 (Reuters) - Less than a third of Europeans are aware of all their rights under last year’s General Data Protection Regulation (GDPR), the European Union said on Thursday as it launched a campaign to encourage more of them to only share data they want to.

Billed as the biggest shake-up of data privacy laws in the internet era, GDPR aimed to give EU citizens more control over their online information and privacy enforcers the power to impose hefty fines on companies such as Facebook and Google that collect large amounts of customer data.

But despite the fanfare surrounding its launch a year ago, the number of people who have tried to change default privacy settings on their social media profiles has fallen by four percentage points since 2015 to 56%, a survey of 27,000 EU citizens commissioned by the bloc’s executive found.

“Only three in ten Europeans have heard of all their new data rights,” Andrus Ansip, the European Commission’s vice-president for the digital single market said in a statement.

“For companies, their customers’ trust is hard currency and this trust starts with the customers’ understanding of, and confidence in, privacy settings,” Ansip added.

Using the new rules, campaigners this month filed complaints to regulators in nine EU countries over how Google deals with data in online advertising.

Although 73% of Europeans had heard of at least one of their data privacy rights, which include the right to be forgotten and access personal data collected by companies or organisations, over a quarter had not heard of any of those provided for under GDPR.

And while the majority of Europeans surveyed said they read privacy statements, only 13% did so fully.

The Commission, which will report on how the law has been applied next year, said this was because the statements were too long and called on companies to make them concise, transparent and easily understandable. (Reporting by Daphne Psaledakis; Editing by Alexander Smith)