Miscalculating monthly stats

[szax]

I have the following entries:
DATE KM LITRES
12/06/2014 213 11,08
05/06/2014 176 9,52
29/05/2014 198 11,66
26/05/2014 217 12,09
20/05/2014 215 12,59
14/05/2014 215 5,69

Basics stats for last month (current date is 13/06/2014)
Mini Stats Total km tracked : 1234 km (adds all 6 entries)
Mini Stats Total litres fueled : 56.95 litres(adds only 5 entries)
Mini Stats Avg L/100km : 4.6 L/100km (using above error numbers)

For some reason the total km mini stat using last month criteria find 6 entries and the total litres mini stat using again last month find only 5.
The same error seems to exists into the avg L/100km mini stat.