Hire cars are included in the ports authority's data.
Minimum one per cent of fleets must be zero emissions.
Climate change law requires information to be supplied to the government.
The total number of hire cars has fallen by some 50,000.
An estimated 75,000 hire cars on the islands.
Podemos are to urge island councils to comply with national law on climate change.
The total fleet is down by some 50,000 vehicles.