I have taught and asked that question before and this is my stand..
THis statistics should refer to the people who play the piano regularly and not people who know how to play the piano but never plays it.
Artist and virtuoso are sometimes immiscible let us say for every 100 pepole who knows how to play the piano. One out of 8 of those pianist (This is estimated through data from the internet and some intuition) have played at least two etudes
Note that even Chopin Etude Op.10 no.9 is already very hard
And out of those people who played an etude one out of seven of them have standard virtuosity.
and out of the middle virtuoso people one out of nine of them are as good are super-virtuoso
making this equation:
1/8 x 1/7 x 1/9 =1/504 ( or one out of 504 pianists are as good as Yundi lee )
this is based on a certain statement of a person about the twelve transcendental etudes by Franz Liszt that only five at a time in the whole world can play one of the twelve etudes...
Then calculate how many piano's steinway can make in a year. Multiplied by the number of piano makers mentioned in Wikipedia (x2)
and multiply them by sixty then divide it by the number of people on this world which in the number of people in this world was already divided into four...
Giving the result that there are currently 220,000 to 276,000 piano's existing in this world at this time therefore if we divide the number of people to the number of piano's then we can conclude that there are 26000~32000 pianists in the world so then what can we conclude then let us determine how many of us have played an etude completely...
Let us make a fixed nuber median of 29,500
29,500 x 1/8= There are 3,687 people who had played at least two etude.....
Then we should determine how many near to virtuoso pianist are there in the world
3,687 x 1/7= There are 527 people who are as good as Yundi Lee
THen out of these virtuoso pianists then we should determine the Franz Liszt mode....
527 x 1/9 = There are 58 and one half people who are as good as Franz Liszt (THe other half is me)....
Talking of creativity then the odds of getting an I.Q above 130 is one is to 25.
This is based from an account in the internet.
Then to the number of composers in this world according to one accounts 17,000 therefore
1/25 x 17,000 = 680 composers with I.Q. above 135 of Gifted ( Kajiura Yuki is one of them)
then If we really need to find the odds of very good composers being super virtuoso's are
(58/29500) x (680/17000)= 39440/501500000
I had a hard time to simplify:
Then we can conclude that One out of 12,040 pianists are very gifted composres and super virtuoso's. I wish I was the one and you too would have wished the same as we'll
we are not talking about the number of people in the world
WAIT! What are the odd's of high skilled pianist that they will join the conservatory..... or will have a job related to music..
Simple then the odds are 1/16~25 and we will fix it to one is 1/25....
Then the chance of Franz Liszt existing today would be one out of 240,800 pianists...
Lizst phenomenon.