The rate in the over 99th percentile group didn't change for girls and changed little over the study period for boys.
女孩体重指数高于第九十九百分位的没有变化，男孩在整个研究期间有稍微的变化。
2
So it's possible that enhanced tectonic activity and a change in climate eroded large amounts of phosphorous-rich rocks, which washed into the ocean over a period of several hundred million years.