Assuming you don’t plan to invest your money and time translating your entire store into another language, you should consider the English speaking population of your selected audience. The following is a list of English-speaking population by country, sorted by number of total English speakers.

Note: The results showed are of people who say that they can speak English, while that was not verified;

Country Eligible population Total English speakers Total English speakers (%) As first language As first language (%) As an additional language As an additional language (%)
 United States 296,603,003 283,160,411 95.46 234,171,556 79.0 48,988,855 16.5
 India 1,028,737,436 125,344,737 12.18 226,449 0.02 125,118,287 12.16
 Pakistan 188,400,100 108,036,049 57 8,642,883 8 92,316,049 49
 Nigeria 156,493,000 79,000,000 53.34 79,000,000 53.34
 Philippines 100,437,852 64,025,890 63.73 36,935 0.0037 63,988,955 63.72
 United Kingdom 64,000,000 59,600,000 97.74 54,400,000 92.14 5,128,000 5.60
 Germany 80,600,000 45,400,000 56 272,000 0.338 45,100,000 56
 Canada 33,121,175 28,360,240 85.63 18,858,980 56.94 9,501,260 28.69
 Costa Rica 4,910,526 400,415 8.2 400,415
 France 65,350,000 23,000,000 39 23,000,000
 Australia 21,394,309 17,357,833 97 15,013,965 70.17 2,343,868 17
 Italy 59,619,290 17,000,000 34 17,000,000
 Bangladesh 163,323,100 30,108,031 18 709,873 29,398,158
 Egypt 83,289,500 28,101,325 35 28,101,325
 Thailand 63,038,247 17,121,187 27.16 17,121,187
 Netherlands 16,770,000 15,030,000 90 15,030,000
   Nepal 29,890,686 10,700,866 35.8 20,000 0.067 876,720
 South Africa 52,981,991 16,424,417 31 4,930,510 9.3 11,493,907 22
 Poland 38,501,000 14,300,000 37 100,000 14,200,000
 Turkey 70,586,256 12,000,000 17 12,000,000
 Iraq 31,700,000 11,095,000 35 11,000,000
 Sri Lanka 22,480,000 10,565,600 47 37,061 0.2 9,680,000 47
 Spain 47,190,000 10,400,000 22 10,400,000
 China 1,210,000,000 10,000,000 <1 10,000,000
 Brazil 205,000,000 10,542,000 5 292,000 0.14 10,250,000 5
 Sweden 9,921,541 8,200,000 86 8,200,000
 Kenya 43,013,431 8,100,000 18.83 7,900,000
 Cameroon 19,740,000 7,500,000 38 7,500,000
 Malaysia 27,170,000 15,580,000 62.57 380,000 1.4 15,200,000 61.1
 Russia 138,312,535 7,574,303 5.48 2,522 7,571,787
 Belgium 10,584,534 6,250,000 60 6,250,000
 Israel 7,303,000 6,205,000 84.97 100,000 1.37 6,105,000
 Austria 8,415,000 6,150,000 73 6,150,000
 Romania 19,043,767 5,900,000 31 5,900,000
 Zimbabwe 13,349,000 5,550,000 41.58 250,000 1.87 5,300,000
 Greece 10,787,690 5,500,000 51 5,500,000
 Sierra Leone 5,866,000 4,900,000 83.53 500,000 8.52 4,400,000
 Mexico 120,664,000 15,686,262 12.9 15,686,262
 Denmark 5,543,000 4,770,000 86 4,770,000
  Switzerland 7,637,300 4,680,000 61.28 73,400 0.96 4,606,600
 Morocco 32,770,900 4,587,926 14 4,587,926
 Norway 5,136,700 4,500,000 90 4,500,000
 Ukraine 40,044,238 7,207,962 18.0
 Republic of Ireland 4,422,100 4,350,000 98.37 4,122,100 93.21 237,900
 Singapore 5,607,300 4,218,737 83.1 1,873,302 36.9 2,345,435
 Ghana 27,000,000 18,000,000 66.67 18,000,000
 Tanzania 40,454,000 4,000,000 9.89 4,000,000
 New Zealand 4,275,100 3,673,623 97.82 3,673,623 85.93
 Finland 5,410,000 3,800,000 70 3,800,000
 Portugal 10,623,000 2,900,000 27 2,900,000
 Papua New Guinea 6,331,000 3,150,000 49.76 150,000 2.37 3,000,000
 Liberia 3,750,000 3,100,000 82.67 600,000 16 2,500,000
 Jordan 6,598,000 2,969,370 45 2,969,370
 Jamaica 2,714,000 2,650,000 97.64 45,900 17.1 50,000
 Algeria 35,954,000 2,516,780 7 2,516,780
 Uganda 30,884,000 2,500,000 8.09 2,500,000
 Hong Kong 6,808,433 3,136,784 46.07 238,288 3.5 2,898,496
 Czechia 10,562,214 2,850,000 27 2,850,000
 Argentina 42,192,500 2,752,681 6.52
 Yemen 24,800,000 2,232,000 9 2,232,000
 Croatia 4,555,000 2,200,000 49 2,200,000
 Colombia 47,661,368 2,012,950 4.22 75,600 1,937,350
 Hungary 9,982,000 2,000,000 20 2,000,000
 Puerto Rico 3,991,000 1,940,000 48.61 100,000 1,840,000
 Zambia 11,922,000 1,910,000 16.02 110,000 1,800,000
 Bulgaria 7,640,238 1,900,000 25 2,605 1,902,605
 Kazakhstan 12,156,705 1,874,583 15.4 602 1,873,981
 Lebanon 4,265,600 1,706,000 40 1,706,000
 Chile 16,634,603 1,585,027 9.53
 Rwanda 10,137,400 1,520,610 15 1,520,610
 Slovakia 5,397,036 1,400,000 26 1,400,000
 Trinidad and Tobago 1,305,000 1,145,000 87.74 1,145,000
 Slovenia 2,050,000 1,210,000 59 1,210,000
 Lithuania 3,053,800 1,160,000 38 1,160,000
 Latvia 2,070,371 950,000 46 950,000
 Guyana 751,000 680,000 90.55 650,000 30,000
 Botswana 1,639,833 630,000 38.42 630,000
 Estonia 1,294,236 650,000 50 650,000
 Cyprus 839,000 610,000 73 610,000
 Malawi 13,931,831 540,209 3.88 209 540,000
 Lesotho 1,795,000 500,000 27.86 500,000
 Suriname 470,784 410,000 87.09 260,000 150,000
 Malta 453,000 400,000 89 48,000 352,000
 Namibia 1,820,916 314,000 17.24 14,000 300,000
 Luxembourg 509,000 290,000 56 290,000
 Bahamas 330,549 288,000 87.13 260,000 28,000
 Barbados 279,000 275,000 98.57 262,000 13,000
 Belize 301,270 246,000 81.65 190,000 56,000
 Madagascar 23,042,300 4,147,614 18 4,147,614
 Mauritius 1,264,866 202,000 15.97 2,000 200,000
 Vanuatu 215,446 180,000 83.55 60,000 120,000
 Fiji 853,445 176,000 20.62 6,000 170,000
 Solomon Islands 552,438 175,000 31.68 10,000 165,000
 Guam 173,456 158,000 91.09 58,000 100,000
 Brunei 381,371 144,000 39.07 10,000 134,000
 Saint Vincent and the Grenadines 120,000 114,000 95 114,000
 U.S. Virgin Islands 108,448 113,000 95.97 98,000 15,000
 Grenada 110,000 100,000 90.91 100,000
 Samoa 188,540 94,000 49.86 1,000 93,000
 Isle of Man 80,058 80,000 99.93 80,000
 Myanmar 53,900,000 2,400,000 4.45 2,400,000
 Saint Lucia 165,000 71,000 43.03 31,000 40,000
 Northern Mariana Islands 84,000 70,000 83.33 5,000 65,000
 Antigua and Barbuda 85,000 68,000 80 66,000 2,000
 American Samoa 57,345 45,933 80.1 1,791 44,142
 Federated States of Micronesia 111,000 64,000 57.66 4,000 60,000
 Bermuda 65,000 63,000 96.92 63,000
 Dominica 67,000 63,000 94.03 3,000 60,000
 Marshall Islands 59,000 60,000 98.33 60,000
 Swaziland 1,141,000 50,000 4.38 50,000
 Aruba 104,000 44,000 42.31 9,000 35,000
 The Gambia 1,709,000 40,000 2.34 40,000
 Saint Kitts and Nevis 50,000 39,000 78 39,000
 Cayman Islands 47,000 36,000 76.6 36,000
 Seychelles 87,000 33,000 37.93 3,000 30,000
 Gibraltar 28,875 28,875 100 28,000 875
 Tonga 100,000 30,000 30 30,000
 Kiribati 95,000 23,000 24.21 23,000
 British Virgin Islands 23,000 20,000 86.96 20,000
 Palau 20,000 18,500 92.5 500 18,000
 Andorra 81,222 17,869 22 17,869
 Anguilla 13,000 12,000 92.31 12,000
 Nauru 12,000 11,600 96.67 900 10,700
 Cook Islands 20,200 4,000 19.8 1,000 3,000
 Montserrat 5,900 4,000 67.8 4,000
TOTAL 5,102,585,737 1,179,874,130 336,358,172 838,676,510