All depends on the quality and precision of the source writing, and the vocab and idioms in the dictionaries. My team translated all the UNIX man documentation into major european languages in 1986 using a machine translation system - over 95% good first pass then polished by the linguists. Also used to do a lot for IBM & DEC as well as our own stuff (ITT).

I was quite well known on the MT circuit then, featured in various media etc. Machine Translation was the "coming thing". Unfortunately it doesn't seem to have made much progress since I left the field in 1987, although there is some very interesting work going on in statistical translation (statistical analysis to determine the most probably correct translation).