As far as I recall, the international versions of SMW show that you've completed everything with a star and "99" in a thinner font (or graphic tile). That's what I was referring to when I used "100%." (Vaguely remember the Tubular issue, though...)
(Edit: Oops, make that
96. And, apparently, the US version is the only one to use the star - the European version just colors the text cyan:
http://tcrf.net/Super_Mario_World/Version_Differences)
(...pulled out my SNES, but excavating my non-import cartridges from my closet will be a challenge (crammed WAY too much stuff in there...
).)