Since North American’s largest online retailer reported its 2013 sales about two weeks ago, its stock price has dropped by about 15% from $403 per share on January 30 to $349 per share yesterday.

Amazon.com Inc. reported a 22% year-over-year jump in global sales—no small feat for a retailer that had to bring in more than $4 billion in additional revenue to grow at that rate—but many analysts view the retailer’s most recent earnings  as a miss for Amazon. Amazon’s $25.6 billion in fourth-quarter sales were in line with the company’s forecast of between $23.5 billion and $26.5 billion in sales for the period, but it fell slightly short of the consensus view on Wall Street, which projected around $26.1 billion.

Part of the miss stems from Amazon’s fourth quarter and full-year sales in international markets, according to senior analyst at Telsey Advisor Group LP, Tom Forte, as foreign sales growth slowed more so than domestic revenue. Amazon’s 2013 international sales increased 13.9% year over year to $29.9 billion, while sales from foreign markets grew 23% in 2012, and 38% in 2011. International sales accounted for 40.2% of Amazon’s 2013 total sales, down from 43% a year ago.

By comparison, North American sales for Amazon grew 27.9% in 2013 to $44.5 billion, only slightly lower than its 30% growth rate in 2012.

“Sales surprisingly came in short,” Forte wrote in his earnings review report.

Amazon did not respond to a request for comment on its international business, but chief financial officer Tom Szkutak said in its year-end earnings call that the retailer, in terms of its foreign markets, was in the “very early stages” of shifting its focus from selling physical media like books and DVDs to digital forms like e-books and streaming movies.

Part of the reason for the slower  growth in international sales may be that e-books and other digital content sold primarily on  Amazon’s  Kindle e-reader—a large part of Amazon’s business—are less popular right now among international shoppers, Forte says. “The (Amazon) digital ecosystem—the Kindle Fire and its content like books, movies, and music—is in the early stages overseas,” Forte says.

Also, while Amazon’s tablet, the Kindle Fire, is now available in all 12 foreign countries Amazon sells in, non-English books and other digital content, like movies, are not yet as widely available in some of those countries, he says. Amazon has country-specific web sites in all the international markets it sells in, but only discloses sales data for its three biggest foreign countries in terms of sales—Germany, the United Kingdom, and Japan.

Web sales grew 20.7% in Germany to about $10.54 billion in 2013 from $8.73 billion in 2012, 12.5% in the U.K. to $7.29 billion from $6.48 billion, but fell more than 2% in Japan to $7.64 billion.

Germany now accounts for 14.2% of Amazon’s total sales. United Kingdom represents 9.8%, and Japan accounts for 10.3%.

The decline in the Japanese market is surprising given that it’s one of the few times Amazon has reported a decrease in sales in a given segment, Forte says. Sales in some international markets like Japan, he says, are being held back because of a less robust consumer spending environment and a slow-moving rollout of native language digital content.

Amazon is No. 1 in the Internet Retailer Top 500 Guide and No. 1 in the Europe 500. E-commerce data in both publications is available in online database format at Top500Guide.com.