Since 1975 so many people have been moving to Utah such that Mormons who were once 75 percent of the population are now only accounting for half of it.

1. so many people have been moving to Utah such that Mormons who were once 75 percent of the population are now only accounting for half of it
2. many people have been moving to Utah, so Mormons once 75 percent of the population are now accounting for only half
3. that many people have been moving to Utah, such that the Mormons that were once 75 percent of the population are now accounting for only half of it
4. many people have been moving to Utah such that the Mormons, who once represented 75 percent of the population, now only account for half

E.so many people have been moving to Utah that the Mormons, who once represented 75 percent of the population, now account for only half

选E, 这种so that 的用法没见过，请教大牛如何理解

 Since 1975, so many people have been moving to Utah that the Mormons, who once represented 75 percent of the population, now account for only half.

so...that...＝太...以致于...

1975年以来，有太多的人一直在搬往Utah州，以致于这里原来占到总人口75％的Mormons教徒，现在只占到总人口的50％。