According to a Kantar Worldpanel ComTech study, sales of Windows Phone devices have decreased in two of the world's largest markets: the United States and China. During May 2014, Windows Phone had 3.8 percent of U.S. smartphone sales, down from 4.7 percent in May 2013. In China, the sales decline was even worse, falling from 3.0 percent last year to just 0.06 percent this year.
Windows Phone sales are stronger in Europe's five biggest markets, accounting for 8.1 percent of smartphone sales. However, in Germany, Windows Phone sales in May declined slightly from January sales numbers.
Experts say that high-end Windows Phone devices are finding it difficult to compete against Android and iOS devices. In addition, the mobile development industry hasn't created as many good apps for Windows Phone as for competing platforms.