想请问一下prep2 209 找来找去找不到解释～～

209. (GWD-10-Q21) Despite the growing number of people who purchase plane tickets online, airline executives are convinced that, just as one-third of bank customers still prefer human tellers to automatic teller machines, many travelers will still use travel agents.


想请问各位NN 后面who跟的是 purchase是意味着 the growing number of people是复数么？但是the number of 不是跟单数形式么？
还是说加了growing使得the growing number 指的是一系列的数值 因此是复数 搭配purchase？

提前谢谢各位了～～



nope


who refer to people  ， not the number of people