Table 5.
Country | 1980–1990 % | 1990–2000 % | After 2000 % |
---|---|---|---|
China | 2.3–5.2 | 3.7 | – |
Canada | – | 2.6 | 3.2 |
United States | – | 4.0–9.3 | – |
Current study | – | – | 11.4 |
Country | 1980–1990 % | 1990–2000 % | After 2000 % |
---|---|---|---|
China | 2.3–5.2 | 3.7 | – |
Canada | – | 2.6 | 3.2 |
United States | – | 4.0–9.3 | – |
Current study | – | – | 11.4 |