I read it's three to ten in the US but I saw a show where it's up to fifteen. As for the machines, I know someone who mines on a much smaller scale but still has a lot of security precautions, it's a tough business.
So if I try to escape from the prison in the US, without harming anybody and without damaging anything I still get additionally 3 to 10 years??
I was surprised to hear that such an attempt was ok in Europe in general, but this goes in my opinion in the exact opposite direction => I can definitely imagine anybody that tries to escape taking extreme measures to try not to get caught to avoid the repercussions.