the article you posted said 375K people was the record # of people at one time on Ibiza and Formentera. not close to 1mm and more in line with what makes sense to me.
I had said 800K people at one time on Ibiza was hard to believe and turns out the all time record # is less than half of that.
Subtract Formentera and look at the average daily summer # its probable more like 200-250K max on the island in the summer outside of August.
for conservancy: 250K visitors on island in a given week, static population
30K Nightly club attendance
One club night every 3rd day, unique visit
Assume Average 'clubber'or 'family' stay is six days, or two unique club visits
Assuming that the clubs are at capacity means:
30K capacity times 6 nights
divided by 2 club visits, each punter
= 90 Thousand ravers out of a total tourist population of 250K, or 36%
In reality, it is likely more complicated as the profile of a clubber and family holiday would be different, as the family stay is likely longer vs a raver's island blitzkrieg
Ibiza has three main groups of tourists, those that like the old hippy vibe, those that like the clubbing and those who just want a beach holiday and pick whatever island/resort takes their fancy on the holiday website.
And important to note not everyone sticks to those groups, in 2017 I did both a clubbing holiday and a relaxing beach holiday in Santa Eulalia. Some may also spend several days on the beach and just a few nights clubbing etc
its a varied island with varied attractions and people and long may that continue
My last visit qualified me as all three of your groups... part of the reason i love the island. I went to the water park and carting with a 5yo, watched a naked hippy braid a leather bracelet, built castles in the sand with a baby and watched a man pull a string of pearls from a woman's vagina at Lio, all in the same week