The number of smartphones sold worldwide has fallen for the first time, but it’s still a ridiculously huge industry.

The figures come from Gartner and are (well-informed) estimates, though the trends should be accurate as the company has been tracking sales since 2004. They refer specifically to sales to users rather than shipments to retailers.

Gartner says sales in the final three months of 2017 totaled 408 million handsets, down 5.6 percent from the same period last year. Samsung and Apple are virtually tied for top spot, making up just over a third of sales between them. Android dominates the operating system, covering nearly 85 percent of sales; iOS makes up 14.4 percent and other systems less than one percent.

While sales in some individual companies have had drops before, this is the first such fall in worldwide sales. Possible explanations include:

• Phones lasting longer.
• Upgrades becoming less attractive as the improvements and new features get more marginal.
• More sales in recent years in developing markets where people are more concerned with getting a phone in the first place than always having the latest model.
• Manufacturers putting more emphasis on high-cost phones to boost revenues rather than concentrating solely on volume.

The decline isn’t exactly a sign of the sky falling in on the smartphone market however. Not only were the estimated sales for the whole of 2017 up 2.7 percent, but the figure topped 1.5 billion for the first time. That’s just short of one in five people worldwide buying a smartphone during the year.