In this week’s instalment of our series tracking cinema’s worldwide winners … Fifty Shades of Grey drops 73% in the Us, meaning Avatar’s record take is safe Jackie Chan ’s Dragon Blade opens big in China but can it breakthrough abroad?• The Interview haemorrhages theatrical revenueFifty Shades still has the global scene trussed up, but dramatic plunges from its opening weekend – -73% in the Us (one of the largest falls on record) and -57% overseas – suggest that it has already exhausted its core audience, the El James faithful, let alone any casuals pulled in by the furore. Strong repeat business looks beyond Sam Taylor-Johnson ’s adaptation, which was cautiously praised as an effective damage-limitation exercise given the shortcomings of the source material. Universal played a blinder on the publicity front, with blanket coverage everywhere contributing to the mammoth, and in many ways historic, opening. The only comparable international