Just to clarify, the period of time it takes for a green card application to process is a factor of:

a: which kind of green card you're getting (employment, family or lottery based are the main ones)

b: where you are applying from (some states will process stuff exponentially faster than others, some processing centers are slow right now due to office re-orgs, and finally anything overseas is going to take you x*4, where x is the time locally)

c: the quality of your lawyer.