Kate Bush's growing love for Running Up That Hill will likely put her on the top this week.

The '80s ballad is already in second place thanks to its use in Netflix's hit series Stranger Things.

His chances of reaching the top have increased after the charts passed a rule that prevents old songs from being penalized for soaring streams.

Running Up That Hill is currently the best-selling song in the UK, with an average of 700,000 streams per day on Spotify.

In previous weeks this flow would have been reported as 3,500 "sells." This week, that number will double to 7,000.

They all stem from the esoteric but essential rules that dictate how charts are calculated in the streaming era. The Top 40 consists of songs you can buy at record stores, and every sale is the same. If the record company hasn't hit enough copies of a 7-inch single or CD, it could lose the charts altogether.

In some cases, record companies stopped producing hit singles to convince people to buy albums instead (Fugees' Wet Wets Love Is All Around and Killing Me Softly suffered the same fate.

But in the streaming era, any song is available anytime, anywhere. Naturally, this poses a problem for the charts. If you count streams by similarity, classics like The Killers' Mr. Brightside will never leave the top 40; modern hits like Ed Sheeran's Bad Habits are currently spending their 50th week in the Top 10.

To give other artists a chance and keep the charts stable, the record industry created "accelerated decline."

That's how it works. A new record wins "sales" if it's served 100 times on a subscription service like Apple Music or Spotify Premium; or 600 times the ad-supported service. But old songs need to attract 200 prime/1,200 ad-supported streams before a "sell-out" is reported.

This leads to the odd situation that Running Up That Hill was the best-selling song in the UK last week (with over 2.5 million streams), but Harry Styles managed to swing in the first place because of his music As It Was; the preferred Stream-sales ratio is delightful. .

The field was leveled this week.