The percentage of congressional races considered somewhat competitive -- a toss-up, or leaning toward one party or the other -- according to the Cook Political Report. The rest are considered likely or solidly for one party or the other.
A bar chart shows the percentage of congressional races considered somewhat competitive -- a toss-up, or leaning toward one party or the other -- according to the Cook Political Report. They ranged between 9% and 27% over the last 30 years. The rest are considered likely or solidly for one party or the other.