What i would like to know though, that may already exist, is the attendance in terms of numbers over the years. I would like to understand if more people are interested or fewer.

It's not about being interested in my opinion. It's about location, who can afford it and in some cases the organizing party counts as well.

As long as the onboarding process is focusing on countries whit broken economy and extremely limited education, where people don't have a pot to piss in, cashing out and spending every penny they earn, don't expect high attendance numbers. African countries are making the top of every shitlist (not accidentally btw), Venezuela as well and very few would be willing to pay to attend. I'm sure if you would get an official list with the location of each HF and the attendance number, you'd see what I mean.