考研英语97年真题阅读passage5,难句请解析，多多多多谢！

Question

America's capacity utilization for example hit historically high levels earlier this year,and its jobless rate（5.6% in August）has fallen bellow most estimates of the matural rate of unemployment----the rate below which inflation has taken off in the past.

<参考书说破折号后面的which引导了一个定语从句，which的先行词是什么呀？翻译出来用当什么是最贴近？请高手指点！！>
which在定于从句中作什么成分？它一般是代词做主语或宾语，这句话中inflation是主语，take off是不及物动词做谓语，那which是什么呢？？

Answer 1

我认为which的先行词是rate
which指的是most estimates of the matural rate of unemployment，
我英语语法不太好，学英语凭的是语感和理解，
毕竟是一种语言，我也考试。有时间可以交流一下英语学习

the rate below which是个定语从句做 inflation的定语 这里 the rate是主语 below 是介词 which 指的是most estimates of the matural rate of unemployment