Nintendo recently announced that the Switch was the fastest-selling console in U.S. history , based on its first 10 months on the market. The announcement came just days after we learned the Switch had also become the fastest-selling console ever in Japan . That’s good news for Nintendo, but what does it really mean? Does it mean the Nintendo Switch

According to Nintendo’s announcement, it sold 4.8 million Switches in the U.S. between March 2017 and January 2018, breaking the record previously held by the Nintendo Wii, which sold about 4 million in the same time frame. Meanwhile, in Japan, Nintendo sold 3.3 million units during roughly the same amount of time.Those numbers are all well and good, but when we talk about which console reigns supreme, we’re usually talking about worldwide sales. So to get some perspective on the Switch news, let’s look at worldwide figures for how the past two generations of consoles have sold globally in their first year on the market.It turns out that even with the worldwide numbers taken into consideration, the Nintendo Switch still comes out ahead. (That is, assuming it reaches Nintendo's sales projection for the year. We’ll know for sure in March, when the Switch turns one.That's an incredible feat on a number of fronts. For one, it shows just how big of a turnaround Nintendo made after the dire Wii U years. In fact, the Switch is on pace to sell more units in its first year than the Wii U did in its entire lifespan. It's also remarkable Nintendo managed to sell that many Switches while facing strong competition from Sony and Microsoft, whose new half-step console upgrades gave their platforms a sales boost.Does that mean the Nintendo Switch is destined to surpass the sales of PS4 and Xbox One and “win” the generation? Not quite. The Switch will win out if it can maintain its remarkable momentum, but that’s far from a sure thing.To see why, let’s look at the last generation of consoles (including Wii U). Because we have a complete set of sales data for those systems, we can see exactly how their first-year sales figured into their total lifetime sales. That will help us predict what kind of lifetime sales the Switch might rack up.The last column in the chart above shows how uncertain the future is for the Switch. Judging by the data, a console's first-year sales don't predict lifetime sales with any accuracy. If they did, the percentages in the third column would be much closer together.If those percentages are anything to go by this generation, that would mean the Switch’s first year sales could make up anywhere between seven and 29 percent of its total lifetime sales. Do the math, and that means the Switch could sell any number between 50 million and 200 million units. That’s a gap wide enough to drive a whole fleet of trucks through.And seeing as Sony has already sold 70 million PS4s , the total Switch sales could easily fall on either side of PS4’s eventual total. (Microsoft hasn’t revealed specific Xbox One sales figures for years, but analysts think it's somewhere near 35 million).So clearly, a console's first-year sales don’t necessarily mean a lot when trying to project total lifetime sales. Sure, the Switch is selling great now, but a lot can change over the course of a console generation. We’ll likely be seeing successors to the Xbox One and PlayStation 4 in the next couple of years, and those consoles are bound to have some kind of impact on Switch sales. Heck, Sony or Microsoft could release a hybrid Switch-like device of their own. And Nintendo could expand its Switch hardware options in any number of ways that could affect sales. There’s no way to know what the future holds.But right now we know the Switch is on fire. It's the fastest-selling console in U.S. history. It already has an impressive library of killer games, and Nintendo has promised heavy hitters like Metroid Prime and Pokémon will be joining their ranks in the future. But if the last console generation is anything to go by, great first-year sales don’t necessarily mean the Switch is guaranteed to eclipse the competition.

Chris Reed is a freelance writer for IGN. You can follow him on Twitter @_chrislreed