The October 2017 term had a low rate of unanimous rulings, with only 39% of the cases decided by unanimous rulings, the lowest percentage since the October 2008 term when 30% of rulings were unanimous. Chief Justice Roberts was in the majority most often (68 out of 73 cases, or 93.2%), with retiring Justice Anthony Kennedy in second (67 out of 73 cases, or 91.8%); this was typical of the Roberts Court, in which Roberts and Kennedy have been in the majority most frequently in all terms except for the 2013 and 2014 terms (though Kennedy was in the top on both those terms). Justice Sotomayor was the justice least likely to be in the majority (in 50 out of 73 cases, or 68.5%). The highest agreement between justices was between Ginsburg and Sotomayor, who agreed on 95.8% of the cases, followed by Thomas and Alito agreeing on 93% of cases. There were 19 cases that were decided by a 5-4 vote (26% of the total cases); 74% of those cases (14 out of 19) broke along ideological lines, and for the first time in the Roberts Court, all of those resulted in a conservative majority, with Roberts, Kennedy, Thomas, Alito, and Gorsuch on the majority.

Who ruled the same as Roberts the most?
Justice Anthony Kennedy