I am looking for a study comparing the strength of party discipline in all democratic countries. Ideally, I would like to see a list of all democratic countries, sorted by the strength of party discipline (this can be measured, for example, by the average number of party-members who vote against the majority opinion in their party, averaged over all votes in given year). I found a study comparing the UK, USA and Canada, but I am looking for a more general one. If no such study has been made yet, I have two more specific questions:
Are there democratic countries with no party discipline at all? Countries where parliament members can vote on each issue according to their own will, without expecting any reprecussions from their party institutions?
What is the strength of party discipline in Switzerland, in comparison to other democratic countries? Is it e.g. in the lowest quartile? highest quartile? or near the median? I found a paper from 1978, but I am looking for more recent information.