Please read a paper on the Shusterman’s immigration web site, July 2005 (
http://shusterman.com/siu.html#1). Some important extractions from the paper are listed below.
About EB-3: “What happens to the EB-3 category on October 1st, the beginning of the new fiscal year? … Just as the H-1B cap fell from 195,000 to 65,000 last October, the total number of EB green cards will fall from 249,000 this fiscal year to 140,000 in the coming fiscal year. ... In all probability, persons in the EB-3 category will face multi-year retrogressions. This means that only people with extremely old EB-3 priority dates will be able to adjust their status.”
About EB-1: “We don't expect the EB-1 category to retrogress any time soon.”