Apple is about to announce that it had its worst quarter in 13 years.

On Tuesday afternoon, Apple is expected to say that its sales and profit both fell last quarter -- a rarity for a company that has been growing at a rapid pace, even as it has become the largest technology company on the planet.

The last time Apple's sales fell year over year was the first quarter of 2003. At that time, the PowerMac was still the company's bestseller. Apple had sold a grand total of 611,000 iPods to that point. And Apple hadn't yet launched the iTunes Music Store.

But as rare an event as an Apple sales decline is, Wall Street analysts are expecting an even rarer occurrence last quarter -- a double-digit sales loss. Apple hasn't suffered that kind of ignominious fate since the fall of 2001. At that point, Windows 98 was the dominant computer operating system, and no one knew what an iPod was, because it hadn't been introduced yet.

Times have certainly changed. Now, more than two-thirds of Apple's revenue is made up of iPhone sales. So where the iPhone goes, so goes Apple -- and last quarter is expected to have been a miserable one for Apple's signature gadget.

Tim Cook predicted in January that iPhone sales would fall for the first time in history. Cook chalked it up to a really great quarter a year earlier, leading to a difficult comparison, on top of a "dramatically different" economic environment now versus 2015.

But ever-sinking iPad sales and flat-lining Mac demand isn't helping Apple's case either.

Apple (AAPL) analysts have their collective fingers crossed that the iPhone 7 can reboot the Apple sales growth machine. in the meantime, the next few quarters are going to be stinkers.

iPhone

First quarter of 2015: 61.2 million

First quarter of 2016 forecast: 50.4 million, down 18%

Barring a miracle, iPhone sales will fall for the first time since the smartphone debuted in 2007.

Demand for the latest iPhone isn't quite as strong as many had hoped. Cook said about 60% of iPhone customers haven't yet upgraded to the iPhone 6 or 6S (or the 6 Plus or 6S Plus).

iPad

First quarter of 2015: 12.6 million

First quarter of 2016 forecast: 10.1 million, down 20%

IPad sales are expected to fall for the ninth straight quarter.

Mac

First quarter of 2015: 4.6 million

First quarter of 2016 forecast: 4.6 million, flat

PC sales fell by 10% worldwide last quarter, according to Gartner. Apple has been outpacing the overall industry.

Wall Street analysts expect Mac sales to fall by the slightest of margins. If that happens, it would be the second straight quarter of falling Mac sales. Prior to the recent slump, Mac sales had risen for eight consecutive quarters.

Profit

First quarter of 2015: $13.6 billion

First quarter of 2016 forecast: $11.1 billion, down 18%

Last time Apple reported earnings, it posted the most profitable quarter in corporate history.

Apple's profit hasn't fallen since the last quarter of 2013.

Sales

First quarter of 2015: $58 billion

First quarter of 2016 forecast: $52 billion, down 10%

Sales are expected to fall. But for some perspective, Apple is expected to have produced more revenue in an off-quarter than the company posted in all of 2009.

Current quarter's sales

Second quarter of 2016 forecast: $47.4 billion

Get used to declining sales. Wall Street analysts expect Apple to post yet another quarter of falling revenue (the third quarter is expected to sink too).

Apple posted $49.6 billion in sales during the second quarter of 2015.

Correction: An earlier version of this article misstated the second quarter forecast.