Researching commercial property rental trends/levels

Can anyone point me in the direction of solid data on commercial rental trends?

I would like to establish and substantiate an rent increase at an upcoming review.

Many thanks
R.A.
(low level poster but high level lurker - would contribute if I only I had a brain.... )

For what its worth I recently had a 5 yr rent review for a retail premises and negotiated a 30% increase.

I'm sure the major agencies release quarterly reports. Might be worth googling.

If yoiu are a landlord looking for a significant increase then wouldn't you be as well to get a specific report from your propoerty/location?