The Friday the 13th had some many "five years" and "ten years later" that some of the entries that were released in the mid to late eighties, probably took place in at least the year 2000.
Robocop never specified the year, it was just obvious that it took place sometime in the near future. Ditto for Clockwork Orange and even Brazil (though since that combines a futuristic atmosphere with a noirish Thirties atmosphere, it's implied that it may take place in an alternate universe.)