Google users are complaining in the Google Web Search Help forums that the "trends" link within their web history is no longer available.
Google web history trends enables you to see trends in your web history such as web activity, including your top searches, most visited websites, daily activity, and other interesting information.
A few days ago, Google removed the feature. Google's Kousha said in a Google Web Search Help:
Thanks for your patience. The good news is that there's nothing wrong with your setups. Trends are temporarily unavailable due to a system upgrade, but we'll have them back next week after regularly scheduled maintenance. Sorry for the confusion!
The picture above is of what I see now versus how Google Trends launched in Web History.
Forum discussion at Google Web Search Help.