Both of these numbers are *technically* correct, they're just different calculations of the click rate. The Response trends graph is calculating the percentage based on total number of campaigns sent, while the mailing's Response page is calculating the click percentage based on total opens.
Here are the stats for this particular campaign:
Total sent: 1505
Total open: 455
Total clicks: 82
The Response trends graph is dividing the 82 clicks by the 1505 sent, which comes to 5%.
The mailing's Response page, is calculating that percentage differently, dividing the 82 clicks by the 455 opens, totaling an 18% click rate.
While inconsistent, both numbers are technically correct. I've sent a note to the Product Owner to change the calculation of one or the other to make them both consistent. I hope this helps!