Output is now six time what it was before 1990.这里的what是什么意思?

Output is now six time what it was before 1990.这里的what是什么意思?

输出（出口）现在是1990年以前的6倍.
句子有错误,应该是：
Output is now six times of what it was before 1990.
what在句中起引导从句的作用.

what引指后边整个后半句
输出是以前的6倍
what在这里代指以前的输出情况

what在这里做双重身份，既做Output is now six time的宾语，也做 it was before 1990的宾语
现在的产量是1990年前的六倍