Please check my math: using your numbers and averaging to 7.5 percent per year, that would be a cumulative increase of (1.075)^5 = 1.44 = 44 percent increase.
Did your rent really go up 44 percent over 5 years? Where do you live?
As an additional data point, I rented a house with some friends in Beaverton for 5 years and the landlord never raised the rent.
I lived in a more expensive apartment than is typical, but there is no housing anywhere near where I am (only apartments). I don't know if proportional increases are typical all over Denver, though. By the end of the fifth year, I was tired of seeing my rent increase at triple the rate of my raises.
I do think for the near future, rent will continue to rise as more people decide to sit out of the real estate market (waiting for more price drops to occur). Ultimately even this should correct itself as people start buying houses again since they will grow tired of increasing prices and decreasing availability of apartments.