The more important question is how many people are playing it in day, week or month. So i played halo 1,2,3 No Reach, Not Really 4 but i played a lot halo 5 and what i can say is that you can play it all the time in every different mode and im from europe.^^
For example 1 year after release halo 3 had peak 75k players on a weekend, so i played 7500 rounds mp in 1 1/2 year, so if you take the numbers from 50-65 k players (peak) every day halo 5 is on the same lvl than halo 3 was and halo 3 was the most sold.
Than Turn 10 said at June or Juley that Forza 6 has more than 3 million players per month and that is >>not<< the most played exclusive, so i think halo 5 is the most played exclusive with perhaps 4 million monthly players at June/Juley 2016 8-9 months after release, after all you can see the diffrence in tracking Xone Games on vgchartz and the reallity because at this moment Forza 6 was at 1.5 million copies with 3 million+ players per month. So there have to be a 60% digital ratio for Forza 6 or it is massive undertracked and we have a digital ratio for halo by 35%in my opionion!