Double Eagle - don'y know about downhill - it has taken me seven years to complete these two sets of business strike Morgans - sticking with just the business strike ones because, frankly, I can't really afford the proof Morgans.
Got a complete set of Peace dollars
, and they're all business strike coins as well.
However, I did start collecting proofs and business strikes beginning with the Eisenhower Dollars, and followed through with the SBA, Sacagawea, Presidential, and ASE
Dollars, so I guess it would be safe to say, I have one of every business strike from 1878 through 2011, and one of every proof from 1971 through 2012.