Google trends shows what query has been searched how many times and some other properties of the said query. But how is this data stored in a database?

Storing a new row for every search does not seem right. They also tell the query on a time graph, so they must have some way to look for individual searches made by users, but the number of queries they get every day, it does not feel right that they would store every search in a database row along with a time-stamp.

This does not apply to just Google trends or Google in general but any other big site that gets awful number of queries and then has tools to see them in depth. I am not an expert on this but I am interested to know some high level structure of how things work behind the scenes.