(NEWSER) – Wondering how safe it is to use your credit card? A long-running study shows that identity theft reached a three-year high in the US last year, striking 12.6 million people, LiveScience reports. Fraudsters ripped off $21 billion, the most in 3 years, and stole an identity every three seconds. What's more, a quarter of American adults notified of a data breach were victimized anyway—meaning people should pay better attention to those notifications. Another sad result: Fraud victims become more cautious about using credit cards with smaller online businesses, but didn't worry about big retailers like Amazon. The study has better advice for avoiding identity theft, however:

• Shred financial documents around tax season. Fraudsters like combing through your garbage.

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