playstation 4
Sony's PS4 continues to outsell Microsoft's Xbox One. Courtesy/Sony

Sony’s PlayStation 4 outsold Microsoft’s Xbox One for the fifth consecutive month, according to NPD Group’s May sales report.

Though the Port Washington, New York-based market research company didn’t reveal the exact sales figures, it did say that the Xbox One, PlayStation 4 and Wii U all sold considerably well last month. The combined sales figures for consoles and portables were $187 million, up 95 percent from $96 million during the same period in 2013.

"While much of May 2014's hardware growth was due to Xbox One and PS4, there was also year-over-year growth for the Wii U, and PS Vita," Liam Callahan, industry analyst for NPD Group, said.

Wii U’s sales increase was due, in part, to the popularity of “Mario Kart 8.” Though the game launched May 30, many people purchased the console before the title’s release in anticipation. The Wii U launched in North America Nov. 18, 2012.

Neither Microsoft nor Sony has revealed the latest exact numbers on their respective devices. In April, Sony announced its PlayStation 4, which launched Nov. 15 in North America, was at 7 million units sold. As of March 31, Microsoft had sold 3 million Xbox One consoles.

“On behalf of the entire global team at PlayStation, I want to thank you for your unprecedented support and for making PS4 your next-generation console of choice,” said Social Media Director Sid Shuman on the PlayStation blog in mid-April. “We couldn’t have done this without you! And please keep the feedback coming: we are listening.”

In early January, Sony President and Group CEO Andrew House revealed that 4.2 million PlayStation 4s had been sold worldwide, as of Dec. 28, 2013. House made the announcement at the 2014 International CES in Las Vegas. The Japanese electronics brand added that the PS4 was its most successful console launch.

"The momentum of the PS4 system keeps getting stronger, and we couldn't be more thrilled gamers worldwide are enjoying the incredibly immersive gaming experiences along with deep social capabilities and entertainment provided by our network," House stated. "After a remarkable launch, we look forward to bringing even more exciting content and continuing to explore the power of the PS4 system by adding new features and services, including PlayStation Now, in 2014."

The PlayStation 4, which launched in North America on Nov. 15, reportedly sold 1 million units within the first 24 hours, which led to 2.1 million consoles sold internationally as of early December. One week later, the PS4’s next-gen competitor, Microsoft’s Xbox One, launched in 13 countries. Microsoft Chief Marketing and Strategy Office Yusuf Mehdi also made an announcement during January regarding the details of Xbox One's sales, saying the console sold 3 million units by the end of December 2013.