Exactly. You could see how many air-bnb flats are in total in a given city on their website and a lot of citiies produce statistics on that. For example in Vienna, the municipality claimed that 3000 air b'n'b bedrooms in a city with millions of bedrooms -roughly 1 ‰ had caused the rents to increase with tens of percent.

Sorry, but people who believe that 1 promile decrease in supply could cause tens of percent increase in prices are just dumb beyond salvation.