=="One way of looking at this question would be to compare the percentage of population kept behind bars by various governments."== 

 This is a false criterion for measuring the freedom of the country, and since the section in question has been reinstated into the article by  (his reason was that it caused a bug) I propose either a rewrite with a valid criterion or deletion.  The Soviet Union had no freedom of speech, freedom of worship, freedom of press, freedom of education (actually they may of), no freedom from slavery (Stalin sent people to gulag camps at will) and their human rights record was appalling as, if not more appalling than the USA.  That is not to say that democracies put limits on some freedoms though, but the USA enjoyed most of the above rights during the Cold War.  Putting people behind bars depends on various factors, and is not a measure of freedom in any sort of country.  Perhaps the nature of the punishments given could be a vague indicator.