Here are some stats from some accounts we manage:
Account #1 CTR 2.7% Conv.Rate 0.86%
Account#2 CTR 2.9% Conv.Rate 2.34%
Account #3 CTR 5.2% Conv.Rate 2.94%
Account #4 CTR 1.8% Conv. Rate 3.5%
Account #5 CTR 3.1% Conv. Rate 19.8%
In this example Account#1 is getting a far better ROI than Account#5 and so is making more money from their AdWords spend.