Question

At 95% humidity, what percentage of the air around us is water vapour? Can you drown? ...?

Answer 1

Humidity is the amount of water vapor in the air. Humidity varies from place to place and season to season.

There are two types of Humidity:
Absolute Humidity and Relative Humidity.
 
Absolute Humidity is the weight of water vapor in a cubic meter of air. The higher the temperature, the higher the ability of air to hold water. For example, at 20 C, the maximum Absolute Humidity is 17.3 g/m^3. At 50 C, the maximum Absolute Humidity is 83.0 g/m^3.  Relative Humidity is the % of water vapor in the air relative to the maximum possible Absolute Humidity.

When we use the word Humidity in ordinary speech, we're talking about Relative Humidity. So,  if the humidity is 95% or even 100%, that doesn't mean 95% or 100% of the air around us is water vapor; just the amount of water in the air is 95% or 100% of the maximum it can hold. 

Therefore, we wouldn't drown at 95% humidity, we will be uncomfortable due to the heat content of air and water but we are still be able to breathe. I hope this answer helps.