Each adoptable pet's 7-day click through rate is displayed in your weekly stats emails, and at
(Once pets are marked adopted or deleted, stats are no longer visible.)
The 7-day click through rate takes the number of times your pet was viewed in search results (hits) and divides that by the number of times the pets full page was viewed (views). So within the past 7 days if your pet was seen in search results 100 times, and was clicked on 10 times, that would be a 10% click-through rate.
It is a good estimate -- but it is not accurate if you are promoting direct links to your pet pages, like say sharing them on Facebook or in an email. If you're doing that, your pet's full page could get viewed a lot from that, and that wasn't the result of a click on their thumbnail photo in search results.