Displays all the important metrics about how you are performing in the search engine result pages (SERPs) including most common search keyword queries, most popular pages, any special rich results and more. The amount of data provided has been expanded to 16 months of data (previously 3 months) which is useful to compare year on year trends.
The top summary chart will show you key metrics including total clicks (how many times users click on your listings), impressions (how many times that your search listings appear in the SERPs), average click-through rate (the rate of clicks divided by impressions), and average position (aggregated average position of all rankings).
You can click on each of these metrics to include them in the reporting table. With the search type option, you can specify whether you want to see web, image or video search results. With the date option, you can change the date range of the report to use other predefined ranges such as the last 16 months or even compare different date ranges, which is very important for comparing performance over time.
The performance report also gives in-depth data around top performing queries, pages, devices and even countries.
Source: Google Search Console 2018