The world’s biggest drugmakers are racing to get in on the world’s fastest-growing health-care market. China's demand for pharmaceuticals has climbed by more than 10% annually over the past several years as the global market slowed. By 2020, China will overtake the U.S. as the largest pharmaceutical market on the planet, accounting for 7.5% of global sales, according to the consulting company IMS Health.
IMS is presumably saying that China will overtake the US in unit volume by 2020; clearly, it won’t come close to overtaking the US in sales dollars.