What is the ERC (European Research Council)? Find more information here:

-ERC website
-Euresearch: the Swiss guide to European research & innovation

Q:How many proposals were evaluated for which grant in which year ?

There is a statistics tool available on the ERC website in the section “Projects & Figures”/"Statistics". This is the  direct link .
You can retrieve any ERC related statistics using this tool. You can sort and filter data according to funding schemes, call year, domain/panel and/or by country of host-institute. To retrieve success rates you can distinguish between evaluated projects and granted projects. Data is exportable as graph and/or csv format.
The statistic tool on the ERC Website is currently under construction with some features not yet in place!