Streaming algorithms appear to be one factor in the reduction.

To put it succinctly, quick hits are ruling 2019.

As previously noted, Lil Nas X's "Old Town Road," atop the Billboard Hot 100 for a ninth week, became the shortest No. 1 hit by song length since 1965, running just one minute and 53 seconds in its original version. Its Billy Ray Cyrus remix still clocks in at under three minutes (2:37).

Elsewhere in the Hot 100's top 10 are such blink-and-you'll-miss-it hits (if your ears could blink) as Post Malone and Swae Lee's "Sunflower" (2:38), Post's "Wow." (2:29) and Sam Smith and Normani's "Dancing With a Stranger" (2:51).

A trend toward shorter hit songs has become evident in recent years. In 2017, Lil Pump's "Gucci Gang," running 2:04, became the shortest Hot 100 top 10 since 1975, while, in 2016, Piko-Taro's "PPAP (Pen-Pineapple-Apple-Pen)" made history as the shortest Hot 100 entry ever: 45 seconds long.

The shrinking of hit songs is even more acute in 2019. Here are some notable stats about the length of Hot 100 top 10s this year (among songs that reached the region for the first time in 2019), according to Hit Songs Deconstructed, which analyzes the compositional characteristics of top 10 Hot 100 hits.

In 2019, the average length for Hot 100 top 10s is a brisk 3:07, a drop of 30 seconds from 2018's average of 3:37. That contrasts with recent years, as the average top 10 song length fluctuated by only 11 seconds (from 3:32 to 3:43) over 2015-17.

Songs under three minutes account for 39% of all Hot 100 top 10s in 2019, a major increase in share. Top 10s that concise gradually grew in prominence from 2016 through 2018, from 4% of all top 10s to 9% to 12% in those three years, before surging more than threefold year-over-year so far in 2019.

The top two longest-leading No. 1s this year both make the category, as the nine-week command (and counting) of "Road" bests Ariana Grande's eight-week reign with "7 Rings," which runs 2:58.

Among hip-hop hits exclusively, year-to-date 2019, the average length for Hot 100 top 10s has plummeted to just 2:48, a drop of 51 seconds from the 2018 average. The average length of hip-hop top 10s actually increased by 38 seconds from 2015 through 2017 (3:13 to 3:51) and then dipped by 12 seconds (to 3:39) in 2018, before its 2019 freefall.

Similar to the rise in share of all-genre top 10s under three minutes, as noted above, such hip-hop hits increased slightly in presence in recent years, from 9% of all hip-hop top 10s in 2016 to 11% in 2017 and 15% in 2018. This year? They've skyrocketed four times over to a 60% majority.

What seems to behind the stark trend? Perhaps, shorter audience attention spans in a TL;DL multimedia landscape. Also, possibly, an aim for more robust streaming totals across artist catalogs, as shorter songs translate to streams of more individual songs within a given listening period.

Additionally, streaming service algorithms appear to play a factor in the recent reduction of average hit song lengths. Those in the industry contacted suggest that digital service providers pay close attention to play-through rates, so, naturally, a shorter song has a better chance of being streamed fully than a longer one. As those stats can help determine playlist placement, artists, management and label A&R departments seek to capitalize.

Meanwhile, on-the-go listeners can enjoy the perk of squeezing in more songs in a particular session, such as a commute or workout.

"Writers and producers' time is fractured like everyone else's, and song length weighs into the tracks they're working on," says one industry source. "They are definitely taking into consideration the culture we live in."