In May 2018, fuel in Slovakia averaged €1.417 for petrol

Petrol, monthly average€1.417/L
Diesel, monthly average€1.287/L
LPG, monthly average€0.582/L
Weekly bulletins held for May 20184

Monthly averages for Slovakia across May 2018, from the stored EU Weekly Oil Bulletin monthly history (European Commission, CC BY 4.0).