Google shared a new report in the Transparency Report for HTTPS both by Google properties and the top sites on the web.
It appears that Google has encrypted 77% of their traffic to date but is aiming to go to 100%. Here is a chart showing their improvement over time with this metric:
Here is a chart by Google product:
And here is one by country:
On the "top sites" which Google determined by using Alexa data and their own internal data, about 25% of those sites are encrypted. You can see which sites are on that list over here.
