Determine the share of electrical use

My employer tells me that I have to drive at least 30% electric with the Hybrid-V60. But what is creepy for me: How does he or I want to measure this? The Volvo app indicates in the travel book the consumption by liters and kWh – but I can’t yet get a (evidenceable) bill. Has someone already had experiences with this or does anyone know a formula with which to calculate it? – You notice: Math is ́not my thing…