I'm kinda curious as to what the history of UA Flights to China is? When were each of the 7 routes started and what equipment was operated during different time periods?

SFO-PEK ==> I'm guessing this one was first?
SFO-PVG
SFO-HKG
ORD-PEK
ORD-PVG
ORD-HKG
IAD-PEK ==> I know this one started in 2006 ish, and sometimes becomes IAD-NRT-PEK