The following table shows the results from the second semi-final of Eurovision 2011. It was a big night for choruses in the minor key (only five out of nineteen choruses were in a major key), and seven choruses began on something other than the tonic chord (usually a IV chord, closely followed by the tonic). The qualifying nations are in festive pink, and notice that, despite the fashion for minor keys:
Of the ten qualifiers, eight began their choruses on the tonic.
Of the nine non-qualifiers, only four began their choruses on the tonic chord.
I’m telling you, Europe, tonic chord at the top of the chorus. Major or minor. Go with the odds.
The AABA for Moldova (my favourite of the night, incidentally) indicates that they didn’t use verse/chorus form, but their refrain still began on the tonic.
And Sweden gets a double tick for key changes, because the song already changed key between each verse and chorus, and still gave everyone a big fat key change for the final chorus. That’s some serious Eurovision writing and arranging right there.

Wow that is really interesting! You should get paid for this!
So…you weren’t playing some sort of Eurovision drinking game like the rest of us? That fact alone puts you way out front.
I drank, as befits the occasion, but it takes more than a few wines to blot out my tonic chord detection abilities.