On this week’s music charts, “What a Time to Be Alive,” a new mix tape by the star rappers Drake and Future, opened at No. 1 by a wide margin, it was announced on Monday — a victory for Apple, which had an exclusive deal to release the album first.
But the album’s success is also the latest example of the extraordinary popularity of hip-hop on streaming music services. Throughout 2015, on outlets like Spotify, Rhapsody and Apple Music, releases by hip-hop and rhythm-and-blues acts including Drake, Kendrick Lamar, ASAP Rocky and the Weeknd have consistently posted far higher numbers than those in other genres.
Those results reflect a banner year for hip-hop and R&B music, with a crop of acclaimed albums and a generation of influential stars. But music executives say they are also an indication of the way that listeners consume music these days, with hip-hop’s younger, mobile-connected audience leading a shift away from downloads.
Songs from “What a Time to Be Alive,” which came out Sept. 20, were streamed 40.3 million times around the world in its first week, including 35.1 million times in the United States, according to Apple. Earlier this year, Drake’s “If You’re Reading This It’s Too Late” was streamed 48 million times in one week, according to Nielsen. Mr. Lamar’s “To Pimp a Butterfly” opened with 38 million and the Weeknd’s “Beauty Behind the Madness” started with 57 million one week and 52 million the next.
By comparison, the best week for a rock act this year was Mumford & Sons’ “Wilder Mind,” with 15.4 million in May. Back in 2012, Mumford & Sons set an early record on Spotify when its album “Babel” opened with eight million streams in the United States.
Steve Berman, the vice chairman of Interscope Records, which released Mr. Lamar’s album and Dr. Dre’s “Compton: A Soundtrack,” said the trend reminds him of the arrival of the tracking service SoundScan in the early 1990s, when more accurate data from retailers showed that rap albums by acts like N.W.A. were far more popular than had been thought.
“What we’re seeing is the truth about consumption,” Mr. Berman said.
Unlike downloads or CD sales, which are both slowing, streaming services show how many times fans actually listen to the songs they select. For the first eight months of the year, hip-hop and R&B songs — which are often connected on so-called urban radio formats, and tracked together by data services — represented 17 percent of album sales, but 26 percent of all streams, according to Nielsen.
The reasons for this disparity are not entirely clear, executives say. In addition to the young demographic of the hip-hop audience, one reason may be the genre’s increasing turn toward promotion on social media; acts like Drake and Nicki Minaj, for example, are highly active on social media, and streaming sites like SoundCloud have become the preferred outlets for new acts.
Another factor may be the influence of Apple Music, the company’s new streaming service. According to one analysis last month, the programming on Beats 1, the company’s Internet radio station, has leaned heavily toward hip-hop and R&B acts like Drake, the Weeknd, Fetty Wap and Dr. Dre. “What a Time to Be Alive” was first promoted on Beats 1, where Drake has his own show.
“This isn’t limited to just the biggest new releases,” said David Bakula, a senior analyst at Nielsen. He pointed out that more than 60 percent of the streams in R&B and hip-hop involve songs that are over 18 months old. “It shows that fans of the genre are streaming the latest hits as well as songs from prior years,” he said.
On Spotify, hip-hop’s share of the top 500 artists is up 16 percent over last year, and 24 percent since 2012, according to that service. On Pandora, the leading Internet radio service, four of the top five acts with the most “station adds” — the number of times listeners choose their names of the artists, or their songs, for listening — are hip-hop and urban; the only other top act is Taylor Swift, according to Next Big Sound, a data-tracking service owned by Pandora.
Over all, the number of songs listened to on streaming services like Spotify, Rhapsody and Apple Music, where users choose the songs they listen to, doubled in the first eight months of 2015 compared with the same period last year, according to Nielsen, while song downloads were down 10 percent and album downloads were flat.
The growth of streaming has moved so fast, said Mr. Berman of Interscope, that it is hard to set the numbers for what counts as a breakout hit.
“It’s too early to set the benchmarks,” he said. “They’re changing too fast.”