Interactions as a share of impressions have apparently stabilised at 1.46%, having leapt sixfold from 0.49% to 3.11% from 2014 to 2015, then fallen by half to 1.51% the following year. Interaction data from Google is only available as far back as 2014, so long-term inferences are difficult to make confidently, but 2017's comparatively tame 0.05% fall could suggest the interation rate in China has begun a more stable pattern of variation.
By contrast, click-through rates (CTR) have gone from strength to stength, rising for their third consective year, overall click-throughs making their largest gain since data became available, from...