This week, many Pokemon fans were surprised to find out that Pokemon Let’s GO Pikachu/Eevee have sold tremendously well last year.

Although the games have moved 10 million copies worldwide, Japanese Pokemon fans have discovered a downward trend in the proportion of Japanese sales to worldwide sales for mainline Pokemon titles.

According to Nintendo’s official report, Pokemon Let’s GO Pikachu/Eevee moved 1.85 million copes in Japan, or about 18.5% of total worldwide sales. This is the lowest percentage compared to previous entries in the mainline Pokemon games:

Game : Sales in Japan / Sales worldwide / Percentage

Pokemon Diamond and Pearl: 5.82 million / 17.67 million / 32.9%

Pokemon HeartGold and SoulSilver: 3.94 million / 12.72 million / 30.9%

Pokemon Black and White: 5.49 million / 15.64 million / 35.1%

Pokemon Black 2 and White 2: 3.02 million / 8.16 million (via VGChartz) / 36.8%

Pokemon X and Y: 4.55 million / 16.37 million / 27.8%

Pokemon Omega Ruby and Alpha Sapphire: 3.20 million / 14.17 million / 22.6%

Pokemon Sun and Moon: 3.91 million / 16.14 million / 24.2%

Pokemon Ultra Sun and Ultra Moon: 2.47 million / 8.28 million / 29.8%

Pokemon Let’s GO Pikachu and Eevee: 1.85 million / 10 million / 18.5%

Many Japanese Pokemon fans wonder what this means for the series – are people outside Japan more into Pokemon GO, or is interest in the mainline Pokemon games dying in Japan? Looks like now is the time for The Pokemon Company and Nintendo to keep a close eye on the Japanese market and find out what’s going on.

What do you think? Let us know in the comments.

UPDATE: Added sales data for more titles not found in the source (HeartGold/SoulSilver, Black 2/White 2, Omega Ruby/Alpha Sapphire, Ultra Sun/Ultra Moon) which prove its overall a downward trend and Let’s GO has reached an all time low. Special thanks to Game Data Library for Japanese sales data.