It might have registered a 6-million release record, it might have debuted as the best-selling exclusive in the UK, but even then nobody was close to forecasting just how well Pokémon Sword and Shield was going to sell before the year's end. Now it's official, and it's massive: 16.18 million copies.
The new-generation RPG by Game Freak was released on November 15 for Nintendo Switch, and seeing as how that figure is only for 2019's Q4, it means that figure was reached in exactly a month and a half on the market. It seems as though the controversy around launch, the harsh criticism by some, and even an attempt to boycott the game after the so-called '#dexit' (which even prompted some people to ask Donald Trump to stop it from being sold in the US). In fact, it looks like all this negative attention actually had a positive effect on sales.
To add some perspective to that figure, we have to underline that Sword and Shield has already surpassed the total sales of Pokémon Sun and Moon (16.7 million on Nintendo 3DS, and with more time and more handhelds on the market) and more than likely it'll pass those of Pokémon X/Y (at 16.42 million - it doesn't have far to go).
In fact, Pokémon Sword and Shield enters the Nintendo Switch best-selling Top 5, kicking Pokémon: Let's Go Pikachu & Eevee out (11.76 million), and quickly approaching Zelda: Breath of the Wild (16.34 million), Super Mario Odyssey (16.59 million), Super Smash Bros. Ultimate (17.68 million), and even Mario Kart 8 Deluxe (22.96 million).
Keeping in mind that lifetime sales for recent entries stay at around 16 million, we can place a couple of bets without too much risk: Pokémon Sword and Shield could well become the best-selling entry of the whole series (Diamond/Pearl and, above all, Gold/Silver await ahead), and it's a good shout that it will be the first iteration to surpass the 20 million mark in several years.