This month, the PlayStation 3 turns five. Having sold 55.5 million units worldwide since its launch (according to Sony's most recent numbers), the PlayStation 3 isn't living up to the unreal sales numbers of the PlayStation (102 million units sold since 1994) or PlayStation 2 (153 million units sold 2000), but it's holding its own against its closest rival, and, according to the numbers, will eventually outsell Xbox 360. 

Xbox 360 launched a year earlier than PlayStation 3. It has sold 57.6 million units worldwide according to Microsoft's most recently released numbers. PlayStation 3 is 2.1 million units behind Xbox 360 in units sold, but it's also been on the market for a year less time than its primary competition. 

If you average out worldwide units sold per month of each console, the numbers favor Sony. Over its lifetime of 72 months on the market, Xbox 360 is averaging about 800,000 units sold per month. Over 60 months on the market, PlayStation 3 is averaging 925,000 units sold per month. 

Based solely on averages, if you were to remove Xbox 360's year head start, 57.6 million units sold becomes 48 million units sold. If you were to give PlayStation 3 12 more months to sell, paralleling Xbox 360's lifecycle, PS3's 55.5 million units becomes 66.6 million units sold. 

Xbox 360 is certainly outselling PlayStation 3 in North America, but Europe is a Sony stronghold, and Xbox 360 support in Japan is essentially non-existent. When you take worldwide sales as a whole into account, PlayStation 3 is on a clear trajectory to ultimately overtake Xbox 360 in sales, possibly as soon as next year. 

This isn't an article designed to incite the passions of fanboys and loyalists (though it most certainly will). Rather, this article's goal is to simply point out an oft-overlooked fact about the sales parity between the two HD twins. 

There are a number of opinions on why the gap is rapidly closing. PlayStation 3 has many more exclusive games than Xbox 360 and a free online service. One could easily use the old fallback that Xbox 360's insanely high failure rate earlier in its lifecycle contributed to more consoles being sold. But frankly, that's all conjecture. 

The only fact is that you can't ignore the numbers. 

Colin Moriarty is an editor of IGN PlayStation. You can find him on Twitter.