Why Click is Higher Then the Impression

When I check report on Adsense sometimes I found that Click is higher then Impression. In other word CTR is more then 100%. Is it normal and how it can be happened?In my opinion there are 2 reasons why it can be happened.1. User open link on adsense on new windows/tab.2. Someone use program or script that will click every link on adsense code.3. Google has a problem with their system.Does it save?What I’ve gotten is CTR about 200% with small click and impression. I never gotten higher click that will make CTR above 100%. Until now I still can earn money from adsense. I assume that it’s save. But if you found your click and impression is higher and make CTR above 100% please report this problem to Adsense.