I just picked statistical informations from what I read.
Those sources for the statistical information should by rights be cited. ;)
It is so important to provide credit to the people who tirelessly determined the information that allows us to write the great posts that we do (like this one).
You're totally right. But honestly, that's an information that I wrote on my handbook at class, and I really don't know from where it exactly comes. Knowing that our teacher chooses informations from scientific articles, I think that it comes from an article published in a scientific journal. Anyway, I'll try to find the same information on internet and maybe I can add a link to the post, but the truth is that every articles takes the numbers/statistics from other scientific sources so it's such a difficult task to find the main source. I totally respect people who's hardworking to give us all these beautiful informations btw, that's why I'm always trying to write sentences with my words. Thanks a lot for your comment.
I see, finding the original source in such cases can be hard, but,as you said, with a little help from google you might figure it out. :D