This year obviously can't be the actual release date for software, since MSX computers weren't on the market yet. Following the links to Tagoo, there are other release dates given for the Japanese releases.
The Infocom entries (including the later ones) are most likely unofficial conversions, to my knowledge Infocom didn't release their adventures on tape (except I think, a cut-down version of Zork for the C64). I've seen no evidence of disk MSX releases either.