repository sizes in different versions?

I have an old repository that I think was started with a 1.4.x version
of subversion, then updated in several stages to 1.6.5 without doing any
changes to the repo format. Du says this repository is taking about 38
gigs of disk space. I've recently duplicated this repository using
snvsync from a system running 1.6.6, copying approximately 120,000
revisions. Du says this repository uses 1.9 gigs of disk space.

Is that reasonable - or at least possible? Does it mean I should do
something to compact the original copy?

-- 
   Les Mikesell
    lesmikesell_at_gmail.com