Hmmm I'm not so sure awakened population would ever reach 100% even when Earthdawn was at the height of its power (horror invasion) and part of a combined universe there wasn't 100% awakening. Personally I'd think it more likely as you get a higher and higher background count you'd get more magically dependant races lamia's, naga's, changelings, harpies, etc and more mystic adepts (or some combination of adept/mage/technomancer) and fewer aspected magicians but you'd never be likely to see even 10% global awakened population.
My bad, for some reason in my head I translated a bunch of the in game flavor text of Earthdawn, the "magic is in everything" bit, as everything is technically awakened/the equivalent of having a positive non-zero Magic Attribute (and the majority still not being "trained" in magic's uses).
Here's some of the parts that make me interpret Earthdawn as the equivalent everyone having a Magic attribute and, with training, can then "use" magic:
* OCC "The world of Earthdawn is filled with magic. The most talented characters, including yours, are initiated in the use of magic. Such characters are called Adepts. Some Adepts train to cast spells, some train to use swords or other weapons, others train to work with animals. The form of magical training chosen by your character is his or her Discipline. This training focuses the magical energies of your character into special abilities called Talents." Earthdawn core book (1st ed, pg 36)
* OOC "[Magic] is the source of the characters' abilities... Magic is a part of everyday life in Earthdawn. It is used to light villages and towns at night..." ibid pg 136
* IC "...magic is such a fundamental part of our daily existence that it pervades our every thought and action." ibid pg 139
* IC "Our world is alive with magical energy, which is ordered into patterns...Any being that wants to use magical energy to cast spells or use talents and other magical abilities must form a tiny part of the magical energy of the world into a pattern. " ibid pg 140
* IC "The act of Naming is important in our world because it focuses the world's magical forces into a True Pattern. From that moment on the Named person, place, or thing is
important in the world. Naming only occurs in the conjunction with the interaction of magic and a person, place, or thing. Magic can be introduced deliberately, through a talent, spell, ritual (suh as a Weaponsmith's Forge Weapon talent, or a child's coming-of-age Naming ritual..." ibid 140.
Since Earthdawn (at least 1st ed) doesn't have a Magic Attribute equivalent to Shadowrun and that essentially with proper training anyone can manipulate magic (according to the training) then my assumption would be that nearly 100% are magically capable but, as you say Senko & Rosa, only 10% reach the heroic Adept levels (though I didn't find a source to that 10% figure, but, interestingly, would match Shadowrun's 10:1 ratio of magically capable to magically trained full magicians).
I think i saw a number once putting the number of adepts in Eartdawn at 10%, i'll try to hunt Down the source. Also i'll try to hunt Down the sources for SR, might take a while since there's a lot of books to look through. One book i'm sure of though is the unfortunately finished but never officially published Shadows of Latin America. In that book Amazonia and Paraguay are put at the 3-4%, Aztlan around the 2% if i recall correctly and i think Ecuador might have been mentioned as having a slightly higher than average number of awakened. I'll go back an check the other books i can think of that have the information.
That'd be awesome for the sources, Rosa, thank you

. I did a search of the Shadows of Latin America book, just searched the document on the following (without the quotes): "2%", "3%", "4%", "2 percent", "3 percent", "4 percent", "two percent", "three percent", "four percent", "double", "triple", "three times", and "four times".
The only thing that came up was about the Aztlan priesthood and that the runner Deprogrammer comments "the percentage of magically active [priests of the Path of the Sun] sits at 24 percent and is rising; much higher than in other sectors or in other religious organizations." (Shadows of Latin America v. 1.2, pg 60).
And I didn't seen anything when I quickly scanned the Paraguay section.