I know that I don't know!
https://external-content.duckduckgo.com/iu/?u=http%3A%2F%2Fwww.thecampingcanuck.com%2Fwp-content%2Fuploads%2F2016%2F12%2Fleap-seconds.jpg&f=1&nofb=1&ipt=c263dfd9fcd403c2277e012682de8763c664ac5411cef56a8181aa472dc5be68&ipo=images
https://what-if.xkcd.com/imgs/a/26/leap_graph.png
https://jjy.nict.go.jp/mission/leapsecond2017-e.jpg