It depends on the agency as well as the country. Every country program has different requirements as well as costs.
I can tell you what our process looked like ( in summary)..
We adopted from China 5 years ago. Our agency was Bethany Christian Services.
3/15/05- mailed application
4/10/05-began USCIS process
8/05- finished dossier and homestudy process ( included USCIS clearances, state and county clearances, medicals, financials, etc)
9/07/05- dossier mailed to China
10/10/05- logged into the Chinese system
2/1/07- referral call
3/7/07- confirmation of Consulate appt.
3/29/07- left for Beijing China
4/3/07- flew to Guangzhou China where we met our dd
4/4/07-finalized by Chinese law
4/13/07- finalized by US law
4/14/07- flew home and dd became a US citizen upon landing in the US
At arrival, 6 months and 1 year we had post placement visits with our SW.
at 9:09 AM on May. 12, 2012