Well, I tried to get this information myself over the last two days. I got a count of 101 of the 143 countries through the worlds but only completed 9 total worlds. My method was using the exhibition games I had to view those teams' countries in each world, then searching for some common user and team names. Then I went through each team's individual schedule and counting each team that had an owner. So here is what I came up with (a ? means I did not find any info, a 0 means I was able to either look at that country or infer that there are no human team managers):
World 59: England: 5, Italy: ?, USA: 4
World 60: England: ?, Italy: ?, USA: ?
World 61: Brazil: ?, England: 2, Italy: ?, Ireland: 6, USA: 5
World 62: England: 5, Ireland: 1, USA: 6
World 63: Belgium: 5, England: 1, Germany: 2, USA: 4
World 64: Canada: 1, England: ?, Germany: 1, Spain: 1, USA: 1
World 65: England: ?, Scotland: 1, USA: ?
World 66: England: 3, Scotland: 3, USA: 15
World 67: Argentina: 1, Czech Rep: 1, Italy: ?, Ireland: ?, USA: ?
World 68: Italy: ?, Ireland: ?, USA: 6
World 69: Brazil: ?, Netherlands: ?, USA: 2
World 70: Brazil: ?, Netherlands: 3, USA: 3
World 71: Germany: 3, Mexico: ?, Spain: ?, USA: 6
World 72: Canada: 6, Scotland: ?, USA: 4, Wales: 1
World 73: Colombia: 2, Poland: 4, Portugal: 3, USA 4, Wales: ?
World 74: Argentina: 1, England: 2, Spain: ?, USA: 6
World 75: Denmark: ?, Germany: ?, Spain: ?, USA: 4
World 76: France: 3, Mexico: ?, USA: ?
World 77: Croatia: 1, Northern Ireland: 2, Russia: ?, USA: 0
World 78: Austria: 2, Czech Rep: ?, Sweden: 5, USA: ?
World 79: Colombia: 1, Denmark: ?, Finland: 2, Israel: 3, Switzerland: 3, USA: 4
World 80: Israel: ?, Japan: 3, Portugal: 1, USA: 7
World 81: Chile: 1, Romania: 1, Scotland: 1, USA: ?
World 82: Ecuador: 2, Netherlands: ?, USA: 3
World 83: Canada: 5, Italy: 5, Norway: 2, USA: 5
World 84: Greece: 3, Ireland: 3, USA: 7
World 85: Brazil: 6, Canada: 13, Hungary: 7, Mexico: 4, USA: 9
World 86: England: 18, Poland: ?, Spain: 3, USA: 13
World 87: Brazil: ?, England: 4, Germany: 7, Japan: 5, USA: 5
World 88: England: 9, Ireland: 4, Spain: 5, USA: 20
World 89: Argentina: ?, Italy: 4, Mexico: ?, Russia: 4, USA: 3
World 90: Brazil: ?, Canada: 4, England: ?, Netherlands: 5, Scotland: 9, Spain: 1, USA: 14
World 91: Argentina: 0, Brazil: 1, Canada: 6, England: 2, Germany: 5, Mexico: 0, Portugal 5, USA: 0
World 92: England: 1, France: 8, Italy: 0, Mexico: 2, Spain: 2, USA: 1
If anyone would like to chime in with numbers from their world, I would be happy to update this. I'm just hoping this gives people a little more information to choose a country and try for different worlds. I also understand every season rollover, these numbers will change