See http://goto.fi/golfpiste for a live implementation (UI in Finnish).
The yearly benefit data (benefit-YYYY.json) only covers Uusimaa region and was painstakingly scraped from http://golfpiste.com/jasenkortti/?p=edut with manual labor and scripts that are too horrible to release.
Licensed under GNU Affero Public License but feel free to ask for changes to that. Uses jquery and jquery-jsoncookie (MIT licensed).
This project is not affiliated with Golfpiste.com.