- Counting car dealership per brand (which is public domain information and available on the above listed sites)
- Counting used car offered online for individual national markets (which can be retrieved from used car websites or corresponding aggregators)
Here we go (luxury used cars listed relative to all used car listings):
Results are broadly consistent with Switzerland and Luxembourg leading the table followed by Italy, France and UK. The low ranking of Germany and USA is somewhat surprising.
Some basic validation of the data can be found calculating when putting Italian (Ferrari, Lamborghini and Maserati) and UK (Aston Martin, Bentley, Lotus, Morgan and Rolls Royce) luxury cars into relationship, with such ratio being particularly high in Italy and low in the UK.