Thirty-one weeks. That's how long the Billboard 200 went without a female artist capturing No. 1. It seems almost impossible, but after Lady Gaga's Joanne bowed at No. 1 on the chart dated Nov. 12, it took until this week (the chart dated June 24) for another solo woman to be credited at the chart's apex, as Halsey took the top spot with sophomore LP hopeless fountain kingdom.

Over that time, more than a dozen male solo artists and groups have occupied pole position -- acts including The Weeknd, Drake, Chris Stapleton, Bon Jovi, Harry Styles and The Chainsmokers -- while the only women to appear on a No. 1 album have been Kirstin Maldonado (of the otherwise all-male group Pentatonix) and the female artists (including Halsey herself) scattered across the track lists of the Hamilton Mixtape and the Fifty Shades Darker soundtrack.

The problem is not just endemic to the album side of the Billboard charts either. Over on the Billboard Hot 100, it's been all dudes at the top for the entirety of 2017 too: A 32-weeks-and-counting streak that dates back to the chart dated Nov. 19 when -- you guessed it -- Halsey was featured on The Chainsmokers' 12-week chart-topper "Closer." And to find a Hot 100 No. 1 with only female artists credited, you have to go all the way back to the beginning of 2016, when Adele's "Hello" enjoyed the last of its ten-week run on top, on the chart dated Jan. 16 of that year.

What's going on here? The easiest, if hardly most satisfying, explanation is that a lot of the biggest female stars happen to be between album cycles: Beyoncé, Rihanna, Taylor Swift, Adele and a number of the other most chart-omnipresent women in pop have all finally exhausted the rollouts from their previous LPs, and the Billboard listings are really feeling their absence in the meantime. One such reliable chart-topper, Katy Perry, finally released fourth album Witness on Friday, and she's forecasted to top the Billboard 200 next week, making it two in a row for female artists. (If it happens, it’ll be the first time women have gone back-to-back at No. 1 since April 9, 2016, when Gwen Stefani’s This Is What the Truth Feels Like succeeded Rihanna’s Anti.)

Even Perry's presence is fading somewhat, though. Witness is forecasted to launch with perhaps 190,000 equivalent album units earned in the week ending June 15, with perhaps 170,000 of that sum coming from traditional album sales. To compare, Perry’s last album, Prism, launched at No. 1 in November 2013 with 286,000 copies sold in its first week, according to Nielsen Music. Meanwhile, her Hot 100 dominance, once among the surest bets in pop, has been conspicuously off for the Witness advance tracks: Lead single "Chained to the Rhythm" debuted at No. 4 but never bettered that initial ranking and quickly slipped out of the top tier, while follow-ups "Bon Appetit" and "Swish Swish" have yet to even crack the top 40. Perry and Halsey releasing their albums in the same month would seem to represent a sort of welcoming aboard among generations of female pop stars, with the 10-year veteran Perry extending an arm to the 22-year-old Halsey to join the club.

But Halsey's not yet a pop powerhouse either. Though it debuted at No. 1, hopeless fountain kingdom's first-week numbers of 106,000 units are actually down from her last album, 2015's No. 2-debuting Badlands -- which moved 115,000 in its opening frame, well before "Closer" made her a household name -- suggesting that she's maintained her always-loyal fanbase but not necessarily expanded it, even with increased mainstream exposure. Meanwhile, lead single "Now or Never" is climbing on the Hot 100 but has yet to crack the top 20 two months after its release -- it's a hit, and her first top 40-charter as a lead artist, but not nearly on "Closer" levels yet, still a ways from establishing her as a true leading lady on pop radio.

We might currently be in something of a dead zone between pop eras, where the old ruling class is starting to recede, but a new one isn't quite ready to replace it. Of those reliable pop perennials previously mentioned, it's conspicuous that all of them have been around since before the return of the decade -- there's yet to be a female act to debut in the 2010s to reach their bulletproof level.

Meghan Trainor seemed she might be on her way after releasing her blockbuster 2015 Title debut, which bested the Billboard 200 and scored three Hot 100 top 10s, including the eight-week chart-topper "All About That Bass." But 2016 sophomore LP Thank You saw diminished returns, peaking at No. 3 and spawning just one top 10 hit, the No. 3-peaking "No." Wild-card pop veteran Sia -- who debuted well before the '10s but only saw her first real U.S. chart success this decade -- has scored No. 1 hits on both charts but remains unpredictable, conquering the Hot 100 with This Is Acting's "Cheap Thrills" but then failing to chart on it at all with the same album's most recent single, "Move Your Body." Alessia Cara may get there soon enough, having scored three top 10 hits since debuting in 2015, but she's still at least an album away from true stardom.

Ariana Grande likely comes the closest, though it took her three singles to score a top five Hot 100 hit off 2016's Dangerous Woman album -- which was also denied the No. 1 spot on the Billboard 200, held off by Drake's Views. She's certainly an A-lister, and after she admirably stepped up to the plate with the One Love Manchester concert upon finding herself at the center of one of the most horrific tragedies any major artist has ever been involved with, her approval rating is currently as universally high as any pop star on the planet's. But just how well that newfound admiration will translate into Billboard-quantifiable metrics like album sales and radio airplay is likely an album cycle away at this point. (She does rebound 4-1 on the Social 50 and 56-8 on the Billboard Artist 100 charts in the wake of the concert.)

Beyond those artists, it's mostly a lot of false starts and unsatisfied promise. Critically acclaimed and fan-adored pop singer-songwriters like Carly Rae Jepsen, Tinashe and Charli XCX all blipped on the national radar with major breakout hits but have been largely (and arguably unfairly) ignored by radio since. Deserved country phenoms Kelsea Ballerini and Maren Morris made significant commercial headway within their base genre but have yet to follow Taylor Swift's path to major crossover success. Groups have not been any more successful than solo artists either: Fifth Harmony may have primed for superstardom, enjoying one of 2016's biggest hits with "Work From Home," but it's unclear how the group will fare since splitting with its most visible member Camila Cabello; comeback single "Down" debuted at No. 42 this week on the Hot 100 (chart dated June 24), just five spots higher than Cabello debuted with her own totally solo debut "Crying in the Club" two weeks earlier.

It's worth asking, though, if the lack of women currently occupying the charts' top tier is due to the artists themselves or changing norms within the charts and top 40 in general. With the increased emphasis on streaming within the industry, pop's center has gravitated toward the music that tends to fare best on those services -- generally favoring hip-hop and EDM, two genres traditionally dominated by male artists. Looking at the current Spotify United States Top 50 chart (as of June 14 publishing), the top 10 is entirely hip-hop and dance -- with the arguable exceptions of Childish Gambino's soul-funk throwback "Redbone" and the genre-crossing Latin smash "Despacito" -- and entirely male. The highest-charting woman on the ranking is Cara, who tellingly appears at both No. 13 and 14 as a featured artist on a hip-hop song (Logic's "1-800-273-8255") and a dance song (Zedd's "Stay").

This upcoming chart week will make for another interesting test case for female pop artists, as Lorde will release her highly anticipated sophomore LP Melodrama. The New Zealand singer-songwriter, who has a Hot 100 No. 1 hit to her credit, has been one of the most prominent fixtures of festival season, and scored one of the year's most buzzed-about singles in "Green Light," could be ticketed for the mainstream's top tier -- but her alt-leaning, not necessarily streaming-friendly sound could also see her relegated to pop's second class. Will she make it three weeks in a row for women on the Billboard 200, with an impressive first week that proves pop reinforcements are on the way? Or will she underwhelm and prove just how serious pop's problem with establishing a next generation of female pop stars really is?