excessive diesel

[B0000M]

Hi everyone,
I have an 07 pathfinder with a yd25 diesel that uses a lot more diesel than any other vehicle i've ever owned.

My l/100km gauge is accurate when measured km vs actual litres used.

Since owning the vehicle nearly a year and 40,000km it has got progressively worse

It's recently had new injectors fitted at the dealership which fixed the loud rattles especially when cold but has made little if any difference to diesel consumption.

If I drive around in mostly 50kph areas going as gentle as possible I can get the gauge down to 14.6. . As soon as I go out to a 100km area for prolonged times this will go up to around 16

I also drive a 550 navara diesel and always see figures under 10

What could cause my pathfinder to use 60% more diesel than the navara?

What is considered a normal figure on one of these with normal daily use?