If anyone's even remotely curious here is the top 20 (out of the songs in the top 40 here) based on WW Spotify streams:

 

1 (17) HEAVEN IS A PLACE ON EARTH BELINDA CARLISLE 1 241,653,576

2 (5) I THINK WE'RE ALONE NOW TIFFANY 1 118,158,856

3 (23) TELL IT TO MY HEART TAYLOR DAYNE 3 116,773,405

4 (15) PUSH IT SALT 'N PEPA 2 109,736,793

5 (18) ORINOCO FLOW ENYA 1 107,479,246

6 (10) TEARDROPS WOMACK & WOMACK 3 64,188,595

7 (6) NOTHING'S GONNA CHANGE MY LOVE FOR YOU GLENN MADEIROS 1 59,882,320

8 (8) HE AIN'T HEAVY, HE'S MY BROTHER THE HOLLIES 2 57,632,576

9 (32) SIGN YOUR NAME TERENCE TRENT D'ARBY 2 54,151,870

10 (1) MISTLETOE & WINE CLIFF RICHARD 1 49,889,721

11 (7) GROOVY KIND OF LOVE PHIL COLLINS 1 48,014,599

12 (14) ONE MOMENT IN TIME WHITNEY HOUSTON 1 47,122,160

13 (27) GET OUTTA MY DREAMS, GET INTO MY CAR BILLY OCEAN 3 30,227,395

14 (40) GIRL YOU KNOW IT'S TRUE MILLI VANILLI 3 28,935,153

15 (35) BOYS (SUMMERTIME LOVE) SABRINA 3 28,031,342

16 (13) PERFECT FAIRGROUND ATTRACTION 1 25,928,439

17 (11) THE LOCO-MOTION KYLIE MINOGUE 2 22,780,638

18 (37) YOU CAME KIM WILDE 3 19,550,760

19 (24) CRACKERS INTERNATIONAL ERASURE 2 14,390,775

20 (28) DON’T TURN AROUND ASWAD 1 14,133,716

 

I didn't include Lovely Day (Sunshine Mix) by Bill Withers here because Spotify combines the plays for the remix and the original but it would be far and beyond at #1 with 315,595,175 plays.

 

Happy to spot that Erasure's wonderful 'A Little Respect' would be #2 on this list ^_^

 

Has any other artist ever had 5 hits in the best selling 21 singles of any year?

 

As others say, the 60's data is unreliable, Billboard compiled a year end chart for the US but it was weeks on chart/points-based not sales=based. That said in 1964 The Beatles would certainly have had 5 best-sellers in the top 20, and they do in the published chart. Most likely it would have been 6 as can't Buy Me Love sold in huge quantities but didnt have the long chart runs as fans were rabidly passionate about The Fab Four. Literally a phenomenon.

 

In the UK the singles were more spread about, The Beatles would have had 4 in 1963, and 4 in 1964 - these are all in the biggest selling tracks of the 60's in various charts published so that's reasonable to assume its correct (I Want To Hold Your Hand had it's sales split over 1963/64 but was an enormous seller, so, like Especially For You I see it appearing in 2 years charts, and high up, possibly all top 10). As The Beatles also sold EP's which were not included in the official charts (Twist And Shout being one of em, the biggest almost-single) and had 2 albums a year, also huge and which would have had split sales of the late-year releases over 2 years, I think it's fair to say they dominated more than any other act in a calendar year overall...Ever. That applies to the streaming era too, cos had there been streaming in 1964 it would have been their young audience using it and all the album tracks would have charted a la Ed Sheeran - physical music was very expensive, make it free and they would have been even bigger and with twice the product of modern acts.