How long would you wait for a proposal?

If you are in a relationship, how old are you and how long would you wait to be proposed to? 
I am 25, he is 26, and i feel like after 3 years, there would be nothing else to know, you either want to or not and another 1, 2 or 5 years probably won't make a difference? We are 2 years in at the moment and are about to move in together.