Rajesh,
It is impossible to predict when one's I-485 will be adjudicated. The process is totally arbitrary. Some people who have I485 RD in 2005 have gotten approvals while some others, like me, have been waiting since 2003 or even earlier.
There are a couple of things you might do. First check if your PD is current. If it is, try to get the status of your FBI name check. Most of the aplications are delayed due to this check (mine included). You can get the status by a few methods
1. If you are lucky, you can get the answer by calling the USCIS 1-800 number OR
2. If you are lucky you can get answer through Infopass OR
3. You can contact your local senator/congressman and have his office inquire about your Name check status from USCIS OR
4. Ask your lawyer to make an AILA inquiry
The 3rd and 4th options take between 3 to 6 weeks. If your PD is current and if find out your name check is cleared, its just a matter of time before your I485 application is approved. Hope this helps
Sanindia
PD Jan 2002
I485 RD Jul 2003
EB2 India