I mean as a franchise it is way more than annual in general
2018: Pokémon Let's Go, Pikachu & Let's Go, Eevee
2018: Pokémon Quest
2018: Detective Pikachu
2017: Pokémon Ultra Sun & Ultra Moon
2017: Pokémon: Magikarp Jump
2017: Pokkén Tournament DX
2016: Pokémon Sun & Moon
2016: Pokémon GO
2016: Pokkén Tournament
2016: Detective Pikachu: Birth of a New Duo
2016: Pokémon Duel
2015: Pokémon Picross
2015: Pokémon Super Mystery Dungeon
2015: Pokémon Rumble World
2015: Pokémon Shuffle
2014: Pokémon Omega Ruby & Alpha Sapphire
2014: Pokémon Art Academy
2014: Band of Thieves & 1000 Pokémon
2014: Pokémon Battle Trozei
2013: Pokémon X & Y
2013: Pokémon Rumble U
2012: Pokémon Conquest
2012: Pokédex 3D Pro
2012: Pokémon Black 2 & White 2
2012: Pokémon Dream Radar
2012: Pokémon Mystery Dungeon: Gates to Infinity
2011: PokéPark 2: Wonders Beyond
2011: Pokémon Rumble Blast
2011: Learn with Pokémon: Typing Adventure
2011: Pokédex 3D
2010: Pokémon Black & White
2010: Pokémon Ranger: Guardian Signs
2009: PokéPark Wii
2009: Pokémon HeartGold & SoulSilver
2009: Pokémon Rumble
2009: Pokémon Mystery Dungeon: Keep Going! Blazing Adventure Squad, Pokémon Mystery Dungeon: Let's Go! Stormy Adventure Squad!, & Pokémon Mystery Dungeon: Go For It! Light Adventure Squad
2009: Pokémon Mystery Dungeon: Explorers of Sky
2008: Pokémon Platinum
2008: Pokémon Ranger: Shadows of Almia
2008: Pokémon Ranch
2007: Pokémon Mystery Dungeon Explorers of Time & Darkness
2006: Pokémon Battle Revolution
2006: Pokémon Diamond & Pearl
2006: Pokémon Ranger
2005: Pokémon Mystery Dungeon: Red Rescue Squad & Blue Rescue Squad
2005: Pokémon Trozei
2005: Pokémon XD: Gales of Darkness
2004: Pokémon Dash
2004: Pokémon Emerald
2004: Pokémon FireRed & LeafGreen
2003: Pokémon Pinball: Ruby & Sapphire
2003: Pokémon Colosseum
2003: Pokémon Channel
2003: Pokémon Box
2002: Pokémon Ruby & Sapphire
2001: Pokémon Card Game GB2: Here Comes Team Great Rocket
2000: Pokémon Stadium 2
2000: Pokémon Crystal
2000: Pokémon Puzzle League
2000: Pokémon Puzzle Challenge
1999: Pokémon Gold & Silver
1999: Pokémon Stadium
1999: Pokémon Pinball
1999: Pokémon Snap
1998: Pokémon Yellow
1998: Pokémon Trading Card Game GB
1998: Pokémon Stadium (Jp. Exclusive)
1998: Hey You Pikachu
1996: Pokémon Blue
1996: Pokémon Red & Green
The only year that hasn't had at least 1 Pokémon game in is 1997