Decimate : Originally meant to destroy exactly one tenth of something. By extension, this has come to mean to destroy a significantly large portion of something, but to leave the majority intact.

Recently this word has been misused to mean to destroy most of something or to destroy something entirely
eg "The Tornado decimated this quiet suburban street.."
This is wrong wrong wrong however I am sure that, semantic drift being what it is, this will become an accepted meaning before long.