With gas, hybrid, electric and now natural gas vehicles now all vying for better gas mileages averages and the marketing fuel efficiency among manufacturers at its peak, it's hard to keep track of what carmakers top the list.

What might come as a surprise, it's not all current models make the all-time list of best gas mileage average — at least dating to 1986 — or the last quarter century.

Here are the top-10 gas mileage average (internal combustion engines) dating to 1986:

1. Chevrolet Volt (2011–12), Plug-in hybrid, 4 cyl, 1.4 L, auto (variable gear ratios), premium gasoline, 60, city; 58 highway, combined, 62.
2. Honda Insight (2000), 3 cyl, 1.0L, manual 5-speed, regular gasoline, 53/49/61.
3. ToyotaPrius (2010–12), 4 cyl, 1.8L, automatic (variable gear ratios), regular gasoline, 50/51/48.
4. Chevrolet Sprint ER (1986), 3 cyl, 1.0L, manual 5-speed, regular gasoline, 48/44/53.
5. Geo Metro (1986) 3 cyl, 1.0L, manual 5-speed, regular gasoline, 47/43/52.
6. Honda Civic CRX HF (1986–87), 4 cyl, 1.5L, manual 5-speed, regular, 46/42/51.
7. Honda Civic Hybrid (2012), 4 cyl, 1.5L, automatic (variable gear ratios), regular gasoline, 44/44/44.
8. Honda Civic HB VX (1994–95), 4 cyl, 1.5L, manual 5-speed, regular gasoline, 43/39/50.
9. ToyotaPrius v (2012) 4 cyl, 1.8L, automatic (variable gear ratios), regular gasoline, 42/44/40.
10. Lexus CT 200h (2011–12), 4 cyl, 1.8L, automatic (variable gear ratios), regular gasoline, 42/43/40.