Apple’s next earnings report is due later this month, and iPhone unit sales alone will probably be enough to move the company’s shares. Analysts from virtually every firm under the sun are releasing their estimates for iPhone units using various data points.

UBS analysts are estimating 69 million units during the December quarter. Stifel analysts are taking a different tactic, looking at import and export data on mobile phones.

U.S. import data suggests strong iPhone unit sales

In a report dated Jan. 8, 2015, analyst Aaron Rakers and his team say there’s a strong correlation between how many iPhones Apple sells and the value of mobile phone imports the U.S. receives from China. They analyzed November data which showed about 32.6 million total mobile phone units being imported. That’s a 23% year over year increase. Combining data from October and November, they found that 58.03 million units were imported. That’s a 16% year over year increase, compared to the previous year’s 4% increase.

Focusing only on China, the Stifel team found that 27.4 million units were imported from China, a 22% year over year increase. For October and November combined, they report that imports from China were 49.05 million, which made up 85% of total mobile phone imports in the U.S. That represents a 16.5% year over year increase.

The Stifel analysts plotted the data on some graphs to show the historical correlation between the number of mobile phone unit imports and Apple’s iPhone shipments. All graphs are courtesy Stifel.

Apple iPhone Sales

Apple iPhone Sales

The value of mobile phone imports

They also looked at the data from another angle, which is in terms of the value of those mobile phone imports and how it correlates with Apple’s iPhone shipments. The analysts reported that the value of mobile phone imports from China increased by more than 30% year over year. The value of the imports for the trailing three months rose by about 28% year over year.

The following graphs show the correlation in dollar value compared to Apple’s iPhone shipments.

Apple iPhone Sales

Apple iPhone Sales

Stifel has a Buy rating and $130 per share price target on Apple stock.

Apple catches up with iPhone 6 demand in the U.S.

A separate report from Apple Insider notes that Apple finally appears to be catching up with demand for the iPhone 6 and iPhone 6 Plus. A check of the company’s online store indicated that the long wait times are finally shortening as all but one model are listed as being in stock. The only model that remains out of stock is the iPhone 6 Plus without a SIM card, but even the wait time on that model is only a day.

Chinese consumers are still having to wait for their iPhone 6 or iPhone 6 Plus, however, as Apple is still requiring preregistration to reserve the phones. Apple Insider also reported that checks at Apple Retail Stores in Hong Kong still show lines to purchase the iPhone 6 or 6 Plus. Some analysts estimate that Apple shipped between 12 million and 14 million iPhones to China during the December quarter.

Shares of Apple stock edged upward less than 1% during regular trading on Friday.