waiting for name check completed and the approval of I485 as a dependent

[wishgood]

Dear All,
I'm dependent on my wife and we filed together last March. She received her I140 and I485 approval last November and official GC this January, but I'm still waiting.
I was told my situation is normal, I mean dependence's application is approved later than his/her spouse's. Is this true?

Does someone know how long I have to waiting to get my name check completed and the I485 approved?

Is there anything I can do to speed up the process?

Thanks