Where are C class long-haul pax disappearing?

Simple question, but I guess with no clear answer.

I started with roughly 25% of cabin for business class. All flights were full, even with terrible price :-)

Now it is less than 10% with superb price, service, ORS rating 100%, connections, interlining... and yet the 10% is filled up only occasionally.

It is not just about me, I checked the ORS and around 95% of all long haul flights aren't fully booked in C.

I understand we have more and more aircraft in the skies, but with economy pax is no problem - my utilization is still 98% for example.

But It seems, according to my calculations, C class shares only 2-3% of all pax, what is a bit strange number...