Should we have to pay two months rent to break a lease at an apartment?

We have lived at this apartment for almost eleven years. About a year and a half ago they upgraded the apartment above us with laminated wood floors. You hear every footstep your neighbors make. We have been miserable. We have complained and complained with no results. We have signed a lease at another apartment apartment and gave 30 day notice. When we turned our 30 day notice in we explained why we were moving, but they already knew why. They said they were not going to put anymore floors like that on the second and third floors. They had learned their lesson. However that didn't help or effect us. I just don't think it should be legal since we lived here and then they changed the floors above us. I am listening to footsteps above me while I am writing this question. I would really appreciate a reply to this question. Thank you very much