Mortgage Origination Estimates for 2004 Start to Climb as Market Prepares for More Refis With 2004 less than three months old, economists already are ratcheting up their estimates for origination volume – and mortgage-backed security prepayments – in response to the very recent drop in mortgage interest rates. Inside Mortgage Finance, an affiliated newsletter, reported this week that the average interest rate on 30-year conventional conforming fixed-rate mortgages fell to 5.29 percent and 1.36 points.