Etherscan is a really useful website but fairly recently I discovered they also have a pretty handy Developer API. I used it to analyse gas a contract was using over a period of time and thought it might be useful to record how I did it.
First of all an API key is required and this can be created for free by logging in and going to: https://etherscan.io/myapikey.
I’m going to paste my code with comments which should be easy enough to follow. The API covers a whole lot of other end point such as Logs, Tokens, etc that I didn’t use but the docs are good and worth a scan.