Does Subversion include compression?

I have a subversion server. On this server I have a folder C:/svn that contain the repositories of 4 projects. Now, one of these projects in pa开发者_高级运维rticular is very large, containing approximately 500 MB of CSV files. However, after I've committed all of them to the SVN server, the C:/svn folder is only 86MB.

How can this be?

SVN does perform compression on the deltas and the repo contents: http://svnbook.red-bean.com/nightly/en/svn.reposadmin.maint.html#svn.reposadmin.maint.diskspace