What Fuel milage will I get?

[AusMBtech]

Tomorrow I'll be driving 800-900km in my 1987 190D 2.5 Manual. The weather is warming up so I'll have the A/C on low most the trip. It's never had injectors serviced and it has 102,000mi.

Let's see who can guess the correct fuel milage for the trip (I'll be cruising at 70mph with some minor hills along the way)

I'm guessing it'll be around 6-6.5L/100km (36-39mi/gal us).

I'll post the results in 2 days.

Options:
1) 25-30mi/gal
2) 30-35mi/gal
3) 35-40mi/gal
4) 40-45mi/gal
5) over 45mi/gal