There has been a lot of hoo-ha in the media about how the voter shift to the Democrats was not nearly as great as is typically the case in mid-term elections. Just to check, I compared the overall vote for the House of Representatives in 1994 with the vote this year.
In 1994, allegedly a banner year for the Republicans, the Republicans got 51.5% of the popular vote for members of the House compared to 44.7% for the Democrats, a little less than a 7 point spread. See here.
This time out, the percentages were 57.7% for the Democrats and 41.8% for the Republicans, a little less than a 16 point spread. That is, better than double the spread of the Republicans in 1994. See here.
However, the total seats won by each party in the two elections were virtually the same, with the Republicans getting 230 seats in 1994 (and with 1 independent) and the Democrats getting 232 (with no independents) this year. The reason that the heavily Democratic vote did not translate into more seats is, no doubt, a testament to the improvements over the last decade in the art and science of gerrymandering.