For my channel, I have the following:
USA- 24.9%
UK- 13.7%
Turkey- 9.0%
Italy- 6.2%
Japan- 5.2%
France- 4.5%
Canada- 4.2%
Germany- 3.2%
Spain- 2.8%
Although you would have to compare those percentages to the number of youtube users from each country to correctly weigh them. I tried to find stats for that but couldn't. Sorry. Can only reweigh them based on the countries' populations (rounded to the nearest million):
USA- 307,000,000
UK- 62,000,000
Turkey- 74,000,000
Italy- 60,000,000
Japan- 128,000,000
France- 63,000,000
Canada- 33,000,000
Germany- 82,000,000
Spain- 46,000,000
So. Let's get some weighted figures. I have a feeling that this method is going to understate the viewership of Spain, Italy and Turkey; by how much I don't know, but keep that in mind:
UK- 67.8
Canada- 39.1
Turkey- 37.3
Italy- 31.7
USA- 24.9
France- 21.9
Spain- 17.4
Japan- 12.5
Germany- 12.0
I looked it up and found out that only about 16% of households in Turkey have internet access (as opposed to 60% in the UK), so I have a feeling that the answer to this question may be, oddly enough, Turkey. But based on my channel (which is contemporary classical, just to be clear), the UK wins pretty handily, which is what I would have expected (although I thought Germany and France would have had much stronger showings, particularly given the fact that the majority of the music I upload is French or German).
Also worth noting: people in China cannot access youtube, so I can't make any statement about them. But based on *my* youtube channel, the UK wins, although I believe that Turkey is actually the answer, given the comparative lack of internet access. If someone is really that interested, you guys might ask a few other people on youtube who upload classical music, preferably people with 2000+ subscribers. And make sure to get channels in various languages, and that tend to upload different eras and concentrations (piano, for instance). I can weigh for different languages based on population (and percentage of native-language-only speakers), percentage of households with internet, then reweigh for the total. If you guys can get me the stats, I can do the math. I doubt the figures would be particularly different, but it could be interesting. Oddly enough, Russia scored incredibly low, only constituting 8 views in the past 30 days. But then again, contemporary music is not very popular in Russia (at all), so a lot of that probably has to do with my channel in particular.
So, us Americans still have to deal with the Brits, but the next time some French or German internet snot tries to tell you how uncultured we are, you can always keep this in mind =P