As of Nov. 27, 2019, according to Update 34, there are 39 State parties to the the Kampala Amendments on the Crime of Aggression.
International Criminal Court, Crime of Aggression -- Amendments Ratification (28/02/2019)
According to Sergey Sayapin, as of early 2014, at least 43 States have enacted criminal legislation against aggression or other crimes against peace. (p. 199)