This is actually pretty common in the elections of every country that uses machines as counters, it's very easy to use them to cheat (I know because I had to simulate one for a project in my university). Most of those machines operative systems can't be read by another one so you can't exactly know if someone changed the software, this was discussed in the Venezuelan elections too and the answer was literally "pineapple you".
In the Venezuelan elections the anomalies are almost similar 8-10% also in cities with high density populations, maybe Romney and Chavez aren't that different after all....
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