Pre 104 请教一句看不太懂的结构

chriswendy36

104. In the United States, while the number of foreign-born residents and their children is higher than ever, the percentage of the population they represent is not, in 1910 this group made up 35 percent of the population, compared with 20 percent in 2000.

我对这题的解法没问题，想请问句子的结构

In the US, while S+V, S+V, S+V

标示的黄色部分是我无法理解的部分，感觉很像流水句

感谢指点

hedongshi

104. In the United States, while the number of foreign-born residents and their children is higher than ever, the percentage of the population they represent is not, in 1910 this group made up 35 percent of the population, compared with 20 percent in 2000.

在美国，虽然外国出生的居民和他们的孩子的数字现在是最高的时候，他们占总人口的比例却无法和2000年时20%相比，在1910年这类人占总人口的35%。