Once made 1000 km with my '92 MKII 1.6NA / AWY Jetta.
Drove at 90 km most of the week and accelerated slowly

Typically we get 800 km / tank summer driving 110 km hour with our fleet of MKII 1.6D Jettas.
My AAZ / K14 MKII GLI clone gets around the same if I stay at or under 100 km hour.
Hugh