40-50% more/day so far (about a week since upgraded to 1.3).
Not sure why bandwidth is a concern in today's world anymore. I have 3TB/month, and I'm not near getting there (using about 0.5TB/month including remote backups). If your hosts limits you to a very small amount of bandwidth, then it's time to move hosts.
My forums are photography forums, so using the Image Proxy dramatically increased our bandwidth usage. From less than 0.5TB/month to over 3TB/month. My host gives me 100TB/month, so I'm nowhere close to the limit, but I'm on a 1Gbps port and probably hit that limit at times.