Acts are eligible for induction 25-years after their first recording and the Rock Hall has long been criticized for snubbing iconic rock groups while inducting acts from other genres like pop, disco and rap.

Deep Purple, who gave the world one of the most iconic rock guitar riffs with "Smoke On Water", has undergone several lineup changes through the years with the most recognized being the mark II lineup of Ian Gillian, Ritchie Blackmore, Roger Glover, Ian Paice and late keyboard player Jon Lord.

Chicago power-pop legends Cheap Trick have been eligible for induction for over a decade and even top selling acts like rock-jazz hybrid Chicago (38.5 million in albums sales in the U.S. according to the RIAA) and Steve Miller (24.5 million U.S. album sales) have been passed over for over two decades.

Rap group N.W.A. will round out the class of 2016 when the induction ceremony takes place at the Barclays Center in Brooklyn on April 8th. HBO will later air a broadcast featuring footage from the ceremony.