Sony’s Jack Tretton has stated via the official PlayStation blog that despite experiencing tight inventory, the PS3 has continued to sell very well since the launch of the PS3 Slim.

Tretton points out that in 2009 at least 15% more PS3 games were sold than in 2008 in all major territories. The growth is in sharp conflict with general software sales which were down 9% in 2009. The PS3 was also the only console to see double digit growth in the USA in 2009, with December being the biggest year ever for the console, shifting just over 1 million consoles and 7.3 million games worldwide.

2009 was not only a good year for hardware and disc sales, but was also the PSN’s biggest year yet, selling 155% more games in December 09 than in December 08.

Although 2009 was an epic year for Sony, 2010 was off to a less prosperous start. In January 2010 Sony sold just 276,000 PS3s around the world, while Microsoft managed 332,000 Xbox 360s and Nintendo an impressive 465,000 Wiis sold. Still, January sales in 2010 were up 36% for Sony over the same month last year, while Nintendo and Microsoft saw single digit figure grow in the month.

Observers are now suggesting that Sony’s inventory issues are having a negative effect on its hardware sales.