I thought this would be mildly interesting. Sadly the SRX does not participate but I do make vehicle notes so I will attempt to fill in the blanks from what I know.
Total miles driven (aka tracked via Fuelly) 2016:
Caprice: 10,189
CTS-V: 1,702
Ranger: 1,528
Ram: 0
SRX: ~11k est.
My fanciest, most complex and most subject to depreciation vehicle gets driven the most. That ought to work out fine. Of course my personal mileage is split between all of the vehicles, and if we just add Caprice + CTS-V + Ranger it is definitely more than the SRX.
Average fuel economy 2016/best fuel economy 2016
Caprice: 16.4/18.9
CTS-V: 18.4/22
Ranger: 17.4/19.8
Ram: N/A
SRX: no idea. Computer says 17.5 average over 20k and I'd guess it has never seen over 20.
It's kind of funny how clustered together these vehicles are.
Total miles tracked via Fuelly (lifetime)/total fuel ups:
Caprice: 45,496 since Feb 2011/165
CTS-V: 17,357 since Feb 2011/79
Ranger: 13,259 since Jul 2011/68
Ram: 483 since Dec 2016/2
SRX: N/A