Reachwerks inaugural newsletter took a look at 2002 versus 2012 rents, they looked at all types of rental properties (apartments, small multiplexes, condo rentals, etc.) who placed ads on SeattleRentals.com.
They also looked at pet policies:
In 2002, 35% of rentals allowed cats and dogs, 30% allowed cats only, and 33% allowed no pets at all. Today, 24% allow cats and dogs, 27% allow cats only, and 47% don’t allow any pets.