Apple CEO Tim Cook said on Wednesday that consumer demand for new iPhones has been “staggering” and “hard to comprehend” and that record sales are due in large part to performance in China.

Shares in Apple surged $8.10, or 7.4 percent, to $117.20 after the tech giant reported record-smashing earnings for its latest quarter. Apple said late Tuesday that it sold 74.5 million iPhones during the three months that ended Dec. 31, beating Wall Street expectations for the latest models of Apple’s most popular gadget, introduced in September.

The new models also helped Apple increase its share of the China market.

Apple doesn’t break down iPhone sales by country, but a report issued on Tuesday estimated that Apple sold more smartphones in China during the last quarter of 2014 than any other maker, including South Korea’s Samsung and the Chinese companies Huawei and Xiaomi.

“Apple was helped by the fact that they sealed a collaboration with China Mobile, the biggest mobile service provider in China,” said Howhow Zhang, Research Director at Z-Ben Advisers in Shanghai.

“And they just started working together so we expect Apple to do even better going forward.”

The surge in iPhone sales drove the company’s total revenue to $74.6 billion for the last quarter of 2014, up 30 percent from a year earlier.

Story compiled with information from The Associated Press.