Trauma Center sold 73,250 copies in December for a total of 119,250 copies in North America. That is less than 2x the November sales so it appears the game sales are slowing down. Japanese sales appear very weak. I think this game will be lucky to top out around 250k worldwide.
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http://www.vgcharts.org/usagamemh.php?name=Trauma+Center%3A+Second+Opinion