As the proud owner of a Volkswagen Lupo 3L, with its legendary mileage of 3 liters of diesel to 100 kilometers I'm trying to find out it the manufacturers claims are true or simply to good to be.

So, here is a list of kilometers and the amount of liters I've tanked. The kilometers are rounded down to the nearest kilometer, and the amount of liters upwards to the nearest tenth of a liter, with only the last 25 data points taken into account.

Data points

liters   kilometers   kilometer/liter   liter/100km   difference
23.6   537   22.7   4.39   +46.3%
24.7   575   23.2   4.29   +43.0%
20.9   544   26.0   3.84   +28.0%
23.6   572   24.2   4.12   +37.3%
49.5   1196   24.1   4.13   +37.6%
18.4   494   26.8   3.72   +24.0%
10.7   258   24.1   4.14   +38.0%
14.3   412   28.8   3.47   +15.6%
10.8   294   27.2   3.67   +22.3%
15.6   434   27.8   3.59   +19.6%
11.3   317   28.0   3.56   +18.6%
11.4   342   30.0   3.33   +11.0%
10.2   296   29.0   3.44   +14.6%
6.7   195   29.1   3.43   +14.3%
11.8   328   27.7   3.59   +19.6%
6.9   239   34.6   2.88   -4.0%
7.1   209   29.4   3.39   +13.0%
10.4   300   28.8   3.46   +15.3%
8.1   251   30.9   3.22   +7.3%
7.0   218   31.1   3.21   +7.0%
12.8   357   27.8   3.58   +19.3%
14.3   411   28.7   3.47   +15.6%
13.8   396   28.6   3.48   +16.0%
24.2   607   25.0   3.98   +32.6%
19.2   524   27.2   3.66   +22.0%

Average value (last 25 data points)

liters
(total)
  kilometers
(total)
  kilometer/liter
(average)
  liter/100km   difference
387.3   10306   26.6   3.75   +25.0%

Average value (full history, 245 data points)

liters
(total)
  kilometers
(total)
  kilometer/liter
(average)
  liter/100km   difference
4360.8   117199   26.8   3.72   +24.0%

Note: The means by which the numbers are calculated and rounded down to 1 or 2 decimals introduces a small margin of error. Usage of this data for any reason whatsoever is therefore neither adviced nor condoned.