CUPERTINO, Calif. — Ending an era of explosive growth, Apple on Tuesday reported its slowest annual increase in iPhone sales since Steve Jobs debuted the iconic device nearly a decade ago.

The Cupertino tech giant also said iPhone sales will slip in the current quarter and projected its steepest year-over-year revenue drop-off in memory.

“It’s clear that weakening demand for the iPhone will impact the company in the coming years,” said Brian Blau, an analyst who covers Apple for technology research firm Gartner. “That weak demand will set expectations that Apple may not be as profitable, or even as popular in the future.”

Concerns had been growing for several weeks that the long-awaited saturation point for the iPhone was near and that sales were about to taper off. And Apple said little on Tuesday to alleviate those feelings. The company sold 74.8 million iPhones in the quarter that ended in December, a less than 1 percent increase from the 74.5 million iPhones it sold in the year-ago period.

On a conference call to talk about Apple’s earnings, Chief Executive Tim Cook admitted demand for the company’s smartphone line is starting to wane.

“We do think iPhone units will decline in the quarter,” Cook said. “We see that (quarter) is the toughest” comparison for the company in year-over-year sales.

The importance of the iPhone on Apple’s overall health is clear, as it remains the biggest source of the company’s revenue. iPhones alone made up $51.6 billion of Apple’s total fiscal first-quarter sales of $75.9 billion, or 68 percent of the revenue in October, November and December.

Apple also said that for the period ended Dec. 26, it earned $18.4 billion, or $3.28 a share. During the year-ago quarter, Apple earned $18 billion, or $3.06 a share, on $74.6 billion in sales. Analysts surveyed by Thomson Reuters had forecast Apple to earn $3.23 a share on $76.5 billion in revenue. The company has about $216 billion in cash and investments.

Although the iPhone claimed the majority of attention with Apple’s report, the company also delivered a mixed bag of results for its other major product lines.

iPad sales declined by 21 percent from a year ago to $7.1 billion, and unit shipments fell 25 percent to 16.1 million tablets. Mac sales also slipped, with revenue down by 3 percent to $6.7 billion, and shipments dipped by 2 percent to 5.3 million units. Sales of so-called “other products,” including Apple TV, Apple Watch, iPods and Beats products, rose 62 percent, to $4.4 billion.