Ubisoft did state publically a while back in a
press release that the series as a whole had sold over 1.5 million units. Traditionally a simulation game was considered successful in the industry with sales of over 300,000 units. The figures Neal quotes may be full price retail ie. before releasing on budget figures? Reading between the lines on various articles it appears that the series is selling more copies in Europe than the US. Indeed SHIII reached number 3 in the UK PC charts on release and stayed in the charts for some time after, unheard of for a subsim.