Apple’s iPhone sales disappointed Wall Street late Tuesday. And the tech giant’s Chief Executive Tim Cook was quick to point to a strengthening dollar as one big factor squeezing the company’s quarterly results.

The Cupertino, Calif.-based gadget maker said iPhone sales grew at their slowest pace since the introduction of the device back in 2007.

But in supplementary material presented along with its fiscal first-quarter results, Apple AAPL, -3.17% pointed to troubles from the greenback and weakness in currencies in Brazil, China and Russia as a headwind for the company that has drawn two-thirds of its revenues from overseas.

Also read:Strong dollar leading to worst stretch for sales since 2009

To Cook’s point, the dollar has gained 20% since October 2014, as gauged by the U.S. ICE Dollar Index DXY, +0.03% —a measure of the greenback against a basket of six rival currencies.

Apple said the strength in the buck meant $100 of Apple’s revenues outside of the U.S. translated to just $85 in 2016, as the following chart from Apple shows:

The dollar has weighed on Apple

Heres' an excerpt of Cook’s comments on Tuesday’s quarterly call via a transcript from FactSet:

“Our results are particularly impressive given the challenging global macroeconomic environment. We’re seeing extreme conditions unlike anything we have experienced before just about everywhere we look. Major markets including Brazil, Russia, Japan, Canada, southeast Asia, Australia, Turkey and the eurozone have been impacted by slowing economic growth, falling commodity prices, and weakening currencies. Since the end of fiscal 2014, for instance, the euro EURUSD, -0.06% and British pound USDGBP, +0.42% are down double digits…The Brazilian real USDBRL, +2.89% is down more that 40% and the Russian ruble has declined more than 50%.”

U.S. companies and, in particular, international behemoths like Apple, have been griping about the drag created by the strengthening buck since the end of 2014.

The dollar began appreciating against most of its rivals back in July 2014 and has ramped higher as the Federal Reserve started to normalize ultraloose monetary policy by lifting rates in December—a move that tends to lift the greenback against its rivals. Adding to global currency woes are plunging oil prices CLH26, , which have dragged resource-linked currencies like the Russian ruble USDRUB, +0.86% and the Canadian dollar to multiyear lows (until recently bouncing higher).

Apple says eliminating the effect of fluctuations in the dollar would have resulted in $5 billon higher revenues globally, including $2.3 billion gained from revenues in Europe:

It is important to note that Apple is using a currency-exchange calculation known as constant currency, which is sometimes used by companies to calculate their financial performance absent swings in, say, the dollar or the yen. Companies tend to use average rates for a currency from prior periods rather than the current value of a monetary unit. A constant-currency exchange is typically used as a way to compare a company’s performance but it isn’t a standard accounting measure accepted by most companies.

In any event, shareholders didn’t seem to be enthused with Apple’s results, sending it down 2.2% to $97.30 late in after-hours trading Tuesday, following its quarterly report.