Viridian City/Demographics

Pokémon Red, Blue, and Yellow
In, the population of Viridian City is 28 (27 excluding Giovanni).

Pokémon Gold, Silver, and Crystal
In, the population of Viridian City is 25. The population has decreased, due to the fact that Viridian Gym no longer has regular Trainers.

Pokémon FireRed and LeafGreen
In, the population of Viridian City is 30.

Pokémon HeartGold and SoulSilver
In, the population of Viridian City is 34. This shows that Viridian City has grown in size from FireRed and LeafGreen to HeartGold and SoulSilver.