According to a data page on NH-DES's web site (
http://www.des.state.nh.us/dam/graph/chart2007.htm) it appears that the lake level has broken a record high for this date by about 0.19 ft. Now stands at 504.83 ft. as of 8 AM today. Lakeport Dam has increased the discharge to just under 1,800 cfs but the last estimate of the inflow (made on Apr. 17) was over 9,000 cfs. I would guess most of it's coming in from below - just like it's been doing in everyone's basements the past few days.
Checking the historical graphs on thier site it looks like last May's high was 505.5 feet and the all-time high (since 1982) was 505.9 feet.