Cameron Wallace recently achieved a perfect composite score of 36 on the ACT.  From the ACT website:

Nationally, while the actual number of students earning a composite score of 36 varies from year to year, on average, less than one-tenth of 1 percent of students who take the ACT earns the top score. Among test takers in the high school graduating class of 2014, only 1,407 of nearly 1.85 million students earned a composite score of 36.