The open House seats in the 2018 midterm elections

New today: House Speaker Paul Ryan won’t run for re-election, a decision whose timing was first reported by Axios’ Jonathan Swan. Rep. Dennis Ross (R-FL) is also retiring, the Tampa Bay Times reports.

By time the midterm elections roll around, there will be at least 58 vacated House seats up for grabs — two-thirds of those are currently held by Republicans. The openings are significant because incumbents have outperformed non-incumbents of the same party in similar districts by about seven points in the last decade or so, per the New York Times.

Notes: The Cook Partisan Voter Index is a measure of how liberal or conservative a district leans based on the two most recent elections. Pennsylvania PVI and vote margins reflect the 2016 district map prior to being redrawn; Data: Daily Kos Elections and Cook Political Reports; Chart: Chris Canipe / Axios