Apple has posted its Q2 2016 earnings results with $50.6 billion in revenue and $10.5 billion in profit from the January to March quarter. These results compare to revenue of $58 billion and net income of $13.6 billion, or $2.33 per diluted share, in the year-ago quarter.

"Our team executed extremely well in the face of strong macroeconomic headwinds," said Tim Cook, Apple’s CEO. "We are very happy with the continued strong growth in revenue from Services, thanks to the incredible strength of the Apple ecosystem and our growing base of over one billion active devices."

Apple’s breakdown of iPhone, iPad, and Mac sales from the quarter:

• iPhone: 51.1 million units
• iPad: 10.2 million units
• Mac: 4 million units

For iPhone sales, that’s an 18% year-over-year drop and a 19% drop for iPads.

Apple sold 10 million fewer iPhones than the tech giant sold during the same quarter a year ago. As a result, Apple on Tuesday reported its first drop in quarterly revenue in 13 years - and the first-ever year-over-year decline in iPhone sales.

Apple's slumping China sales reflect more a slowing economy and stalling market for smartphones. It’s also a sign that local vendors are finally producing high-end devices that can compete with the iPhone.

Chinese consumers seem to be less willing to pay a premium for an Apple product. That is bad news for a company that has been counting on growth in the world’s largest smartphone market.

Overall, the company's revenue in the January-March quarter was down 13 percent from a year earlier.

Apple's revenue for the quarter included $6 billion from online services, apps and other software. That's up 20 percent from a year earlier.

Apple hasn't revealed sales figures for the watch, but most analysts estimate the company has sold 12 million or more, producing well over $5 billion in revenue.