Do not forget that in Europe, the Master System was supported up until 1996, and was discontinued together with the Mega Drive.
hm. Alright, let's try rolling this question up from another angle:
According
to this article, Nintendo (and I quote) "only shipped 8.56m NES consoles in non-Americas & Japan regions".
Furthermore, the book "Game Over" states that Nintendo sold only 3.5 Million NES-units in Europe. <== scratch that, misconception.
The Master System officially sold 13 mio. units worldwide (not counting Majesco- and TecToy-versions). According to
this source, only 1.5 million systems were sold in the US.
That leaves 11.5 Million Master Systems sold outside of Japan and the US. Now, if we could extrapolate how many Sega Master System-units were sold in Brazil, we could get a good estimate of how well the Master System fared against the NES in Europe.
(hm, although this still leaves Australia out of this calculation...)
/edit: found another nice graphic,
LA Times from a british magazine (I don't know which, exactly).
http://img714.imageshack.us/img714/9894/segasales.jpg
1990: 1.6 million SEGA units (although those numbers include Genesis sales) vs 655.000 NES-units sold in Europe. Though I can't say how reliable this source is, what with the Typo ("staggereing") and the somewhat mystifying way to end the article...
Before Jack Tramiel took over, the Atari VCS and home computer systems were pretty successful, so I'd rather say Germany was more of an "Atari"-country... :p