Consumption Aygo long highway ride

Hello everyone, I will make a 600km journey in two days and have the pleasure of driving an Aygo (: 2 people, 2 pieces of luggage. Would I like to know how much the Aygo consumes at Tempo 140 (90% of the distance will probably be the speed) with air conditioning and light on!? Has anyone ever made such a measurement or is there any data online? Would I be interested in burning. Have heard that the small engines consume on the Highway as much as the big !? Thanks, CU