CTR down

Advice please! I manage SEO for a marketing company's website and blog. Clicks and impressions have been increasing over past 6 months but CTR has been trending down - 150% increase in impressions but only 105% increase in clicks. so CTR gone down about 30%

I am looking at pages with high impressions, low clicks; pages that have dropped in clicks and impressions. Anything else I should be looking at? Thanks!