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.