How many drafts?

I began writing The Last Dance over 15 years ago, it was published in 2006. It was followed by Walking Alone in 2007 and Runaways in 2009. Together they made The Iniquities Trilogy.
When I began The Last Dance I knew only in the broadest terms how it was all going to end and I also tried to make each book stand alone as an independent story, so I left too few clues, too few teasers towards the final denouement, in those first two volumes.
In retrospect, I believe that was a mistake so, since mid-May 2015, I have been working them into one.
When I first put the three manuscripts together into a single volume there were 372,165 words in 914 pages. That first complete read through and few odd changes took to the end of July. Instead of reducing in size (which had been my intention) the document had grown to 376,508 words over 917 pages.
The second run through was more of an edit. I began to cut out words, sometimes quite ruthlessly. I cut out incidents and descriptions that really didn’t add to the story – but I began to add in the teasers. When that draft finished a year later (well – I had written another book, Second Strand, and moved house, and worked on the day-job in the meantime) the manuscript was reduced to 342,798 words over 840 pages.
I began the third re-draft in July 2016 and, with no other book, no house move and being almost retired, I completed it in two months. Now at 324,949 words over 792 pages it was still long, but a more reasonable length. It was also a better, tighter and more flowing read.
The fourth run through began in mid-September and there were still sections I wanted to improve and events I wanted to change. By the end of November this draft was completed. (306,352 words over 744 pages).
I am now 30% through the fifth run through with a further 7,088 words and 28 pages having been lost. And I am still changing things. So there will have to be a sixth… and then a seventh… and then…
I suspect this is my Sisyphean task. I will still be working through it, changing it, hopefully improving it for years to come.
Maybe, one day, someone else will read it.