I wrote this in 4 chan and I am posting it again here since you may find it interesting and because there stuff disappears in a matter of hours
The info was taken from a 2007 neogaf thread, the primary school maths are mine http://www.neogaf.com/forum/showthread.php?t=177491&page=2
End of 1991
We know SNES sold 3.4 million units and Sega had 55% of the market, Nintendo 45%
That means
Sega 4.155.555
Nintendo 3.400.000
End of 1992
best SNES year, Nintendo sold 5.6 million SNES units, and outsold Genesis by 10%
that means
Sega: 5.040.000
Nintendo: 5.600.000
End of 1993, both consoles sold less than in 1992, Nintendo 32% less and Sega 24% less
that means
Sega: 3.830.400
Nintendo: 3.808.000
We know that at that time Sega had sold 13.025.955 units in the USA and Nintendo had sold around 12.808.000. So, in December 31 of 1993 Sega was still outselling Nintendo in the USA.
For what happened from 1994 on we have NPD data, which wasn't as precise back then as it is nowadays, but it is still the best thing we have.
NPD Data
GEN vs. SNES:
'94 - 3.62m 3.24m
'95 - 1.89m 2.32m
'96 - 0.85m 1.25m
'97 - 0.33m 0.83m < SNES2 rel.
'98 - 0.57m 0.88m < GEN Core 3 rel.
'99 - 0.32m 0.29m
'00 - 0.04m 0.01m
TOT: 7.62m 8.82m (after 1993)
This means Sega sold 20.645.955 Genesis units and Nintendo sold 21.628.000 SNES units in the USA.
Numbers before NPD are from Steven Kent's History of videogames.
Nintendo claims to have sold 22 million units in the USA, so these numbers seem pretty close to what really happened imo. It was close to a tie, but Sega fucked up with the Add ons, and Nintendo came back with their 1994-1996 games.
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What this means is that the number we have seen so many times of 29 million Genesis/Mega Drives sold worldwide is wrong, because according to it it only sold 17 million units in the USA. I think it definitely sold more than the N64 worldwide, and if we count the ones that continue to be sold by Tectoi in Brasil for example, the number may be bloser to 35 millions than to 30 millions. IIRC 2 or 3 years ago they were selling 150.000 per year in Brasil.
