What is the population ratio of humans and pokemon in the pokemon world (pokemon series)? Considering that every human has more than one pokemon, it might be possible the pokemon ratio is higher.
I don't think there is any specific information about this in the Pokémon anime, manga, or games, but the ratio of humans to Pokémon in the Pokémon world is likely similar to the ratio of humans to other animals in the real world. The estimates listed below are from this article: How Many Wild Animals Are There. The author admitted the estimates are not very good, but I could not find a better source.
Land Birds: 1 * 1011 to 4 * 1011
Land Mammals: 1011 to 1012
Land Reptiles: 1011 to 1012
Land Amphibians: 1011 to 1013
Fish: 1013 to 1015
Humans: 7 * 109
From these, we can get a rough calculation of the ratio of other animals to humans (and thus Pokémon to humans) by summing the different groups of animals (using the higher estimates) and dividing by the number of humans:
1.0124 * 1015 animals / 7 * 109 humans = 144,628 animals per human.
This number should give a general idea of the ratio between humans and animals, but should in no way be taken as accurate. And note that if I added arthropods into the sum, then the ratio would be greater by several orders of magnitude. I didn't do so because bug Pokémon are much larger than their real world counterparts and their populations probably would not be comparable as a result.
Links of interest: