less than 2 years for me.

I applied in May, 2004, got RFE one time for more documentation (myPhD diploma, cause I didnot have one when I submit the package), then approved around March this year, they issued me visa for two month, so I went landing May 20th, 2006.

I'd say less than 2 years. I am not sure whether the score counts, I got PhD, and a few years of working experience.
I prepared all my own documentation by myself. It is really easy,just follow their website.