iCloud does not back this data up, it only syncs it between devices. You may get them back by restoring an iOS device to a back up from before the Notes were deleted.
Apple has also messed up restoring Notes through Time Machine on the Mac but it is probably still your best option. Read https://discussions.apple.com/message/19171700#19171700 to locate the folder then open Time Machine. To get into your Library folder you will have to open a Finder window then click the Go menu and press the "Option" key on the keyboard to make "Library" appear.