Know-How Exchange : Research/Metrics

We're in the midst of a Direct Mail piece to 7500 customers encouraging them to switch from a competitor to us. (Our company offers a variety of inter-related services, so the customers contacted have one or more of our other services. The DM piece is targeting an additional service that we provide.)

The response so far has made the Profit Center Mngr. happy - in the first 2 months approximately 650 customers have switched to us. (The program runs through April.) But I'd like to make sure we're on track.

I've seen the 2%-5% 'rule of thumb' for response rate to Direct Mail mentioned in many places over the years. My question is:

Part one: Is that 'rule of thumb' still applicable and if it is, what percentage of that number should I reasonably expect to actually convert?

Part Two: If the 2-5% is not the accepted anymore... what is the "going rate" so-to-speak?

Thanks so much,
Kate