The Pokemon Games sales news here is a list of when the previous games sold to compare:
From March 2017:
Green, Red & Blue: 31.38 million (Pre-Virtual Console)
Yellow: 14.64 million (Pre-Virtual Console)
Gold & Silver: 23.10 million
Crystal: 6.39 million
Ruby & Sapphire: 16.22 million
FireRed & LeafGreen: 11.82 million
Emerald: 7.06 million
Diamond & Pearl: 17.64 million
Platinum: 7.69 million
HeartGold & SoulSilver: 12.72 million
Black & White: 15.62 million
Black 2 & White 2: 8.52 million
X & Y: 16.06 million
Omega Ruby & Alpha Sapphire: 13.68 million
Sun & Moon: 14.69 million