I'm spending about £5-£7 a day on adwords, and am getting only a couple of enquiries a day at most. For instance yesterday I had 465 impressions and only 19 clicks. Of these clicks I had only a couple of enquiries. Frustrating. As they say in the agony aunt columns, is this normal?
My site used to be well-ranked by google but has since dropped right down (it has no backlinks and I can't seem to get any) - but when it was well ranked in the natural rankings I seemed to have at least equal if not more enquiries - and for free!
But in the end, the CTR has very little to do with whether your ad is doing well. I can put an ad out there that will get an easy 20% - 30% CTR. Of course, no one will buy anything so did it do me any good? Look at your conversion and judge your sucess by that. Everyone has an aim on their site. Are you looking for sales, leads, sign-ups? But a monetary value on them and then see if what you are paying to adwords is less than or equal to your goal. For more info, look into ROI. It is a better judge of your sucess.
When measuring/comparing CTR, check the stats for the search network ads only. This can be done by checking out the CTR of each of the adgroups. Since content CTR is mentioned seperately, you can just ignore them.