| Country | 2014 | 2015 | 2016 |
|---|---|---|---|
| United States | 47.15% | 46.90% | 48.64% |
| Mexico | 27.34  | 27.14  | 27.93  |
| India | 22.92  | 23.13  | 20.51  |
| Pakistan | 18.15  | 23.44  | 22.43  |
| Indonesia | 17.67  | 18.20  | 18.25  |
| China | 17.14  | 17.27  | 17.69  |
| Average | 25.06  | 26.01  | 25.91  |