Kanye West's Fashion Evolution
Meow! Rocking a leopard-print Givenchy jacket, West looks purrfectly sharp with rapper 2 Chainz as they visit 106 & Park Studio in New York City on April 9, 2012.

Just in time for summer celebrations, Kanye West and friends Big Sean, Pusha T and 2 Chainz take their party to No. 1 on R&B/Hip-Hop Songs, as "Mercy" (2-1) gives Usher the boot after 10 weeks on top with "Climax" (1-2). "Mercy" rises by 9% to 27 million in audience, according to Nielsen BDS.

"Mercy," which references the uber-expensive Lamborghini Murcielago, is West's sixth No. 1 on the survey, Sean's second and the first each for Pusha T and 2 Chainz. West is the common denominator on both of Sean's leaders, having been credited as a featured act on the rapper's "Marvin & Chardonnay," which led in October. "Mercy" is the first single from the forthcoming G.O.O.D. Music compilation album due later this year.

Usher's fall to No. 2 prevents a tie for his longest-leading No. 1 with his breakout smash and first No. 1, "You Make Me Wanna …," which topped R&B/Hip-Hop Songs for 11 weeks in 1997. "Climax" slips by 10% to 26 million in listenership.

On the flip side, J. Cole's "Nobody's Perfect," featuring Missy Elliott, takes a 10% leap (to 24 million), jumping 5-3 and continuing to grant Cole his best rank. He had risen as high as No. 7 with two tracks, including most recently with "Can't Get Enough," which peaked at No. 7 in January.

Trey Songz's "Heart Attack" slips 3-4 on R&B/Hip-Hop Songs, while Usher, despite his departure from No. 1, will be just fine: his Rick Ross-laced "Lemme See," the follow-up urban-focused single to "Climax," enters the top five (6-5).

THREE FOR 2 CHAINZ: It's a huge week for rapper 2 Chainz, as he triples up in the R&B/Hip-Hop Songs top 10.

As he leads with "Mercy," he scores his third top 10 with a 14-8 blast for "No Lie," featuring Drake. The cut claims the chart's top Airplay Gainer award with a 43% increase to 18 million. (Let's not forget to mention that this is the ubiquitous Drake's the 25th top 10, all since his 2009 chart arrival.) 2 Chainz completes his top 10 trifecta as a guest on Nicki Minaj's "Beez in the Trap," which dips 8-9.

2 Chainz, Drake, Minaj and Chris Brown are the only acts to sport three titles in the R&B/Hip-Hop Songs top 10 simultaneously this year.

WE'RE 'JAM'-MING: More good news for Usher, as his "Looking 4 Myself" retains its No. 1 position on R&B/Hip-Hop Albums after debuting on top last week. The set did, however, tumble by 62% to 48,000 copies sold, according to Nielsen SoundScan.

Razor & Tie's "That's My Jam," a five-disc compilation album that features some of R&B's biggest hits of the past 20 years, was clearly named after a phrase most music fans have subconsciously shouted out while listening to the radio. The set debuts at No. 2 on R&B/Hip-Hop Albums with 14,000.

The start matches the debut of the label's "Slow Grind," which also opened at No. 2 in August 2011. "Jam"'s bow at the silver spot is symmetrical with "Slow Grind"'s incredible feat: it's the highest rank in the 47-year history of R&B/Hip-Hop Albums for a compilation album of prior R&B-only hits from a host of different record labels.

"Jam" features 19 songs that have topped Billboard's R&B and hip-hop charts from as far back as 1993 from such artists as R. Kelly, TLC, Ginuwine, Toni Braxton, En Vogue, Blackstreet and Usher.

Rounding out the R&B/Hip-Hop Albums top five, Waka Flocka Flame's "Triple F Life: Fans, Friends and Family" falls 2-3 in its second week (14,000, down 58%); Minaj's former seven-week No. 1 "Pink Friday: Roman Reloaded" rebounds 5-4 (13,000, up 11%.); and, at No. 5, the "Project X" soundtrack soars 25 spots (30-5) back into the top 10. Its 403% increase is owed to the film's arrival on home video on June 19. The set peaked at No. 3 in its second chart week in March.