There is an amusing book written on the incorrect use of the apostrophe as you have noted.

Another very common misuse is to refer to a period of time, the 70's with an apostrophe. The correct use is the 70s or the 1970s unless the use is, Bridget Fonda was the 70's child.

But what about text used on websites and more often than should be, in ads where a tic mark is incorrectly used for an apostrophe? But don't get me started.