Prior to the election there were 2,420 House and 874 Senate Democrats and 2,926 House and 1,030 Senate Republicans
. After the election there were 2,584 House and 888 Senate Democrats and 2,785 House and 1,017 Senate Republicans. That represents a 6.8% increase in Democratic House members, and their increase in state Senate seats was only 1.6%.
But remember, Republicans picked up 675 seats in 2010. So to put it another way, Republicans gave up 178, or 26%, of the 675 seats that they picked up in 2010
In addition, 70 percent of that 6.8% is from just one state (115 of the 164 seats), New Hampshire, and that is because that state has 400 state legislators. The information is from the NCSL.org.