Rampage surpassed $90 million at the US box office officially and it is on the verge of passing $400 million worldwide, which it should do this coming weekend with it's last opening in Japan (May 18th). While some will said it's US take is nothing to write home about it's the International side that is more impressive, particularly China.
As it has become increasingly obvious films do not have to have huge takes in the US to be viewed as successful, the first Pacific Rim was one that got approved for a sequel based on the $100 plus million it did in China. In the case of Rampage it's China box office is none to shabby, it currently is at nearly $155 million.
To compare only Kong: Skull Island (of the recent giant monster films) was higher with $168 million, and many Marvel films failed to beat it, even Black Panther which hit only about $105 million there. China is the second biggest market behind the US so a films success there is a big deal and helps in a films bottom line and approval for sequels. $400 million is the sort of magic number for success for big blockbusters (depending on budget, promotion), Rampage falls into that category.
Below is a comparison to other similar action films.
China Box Office Totals (Via Box Office Mojo)