As I wrote before, I am sure most would consider a L1 an expert, and I at least wouldnt consider anyone who did ridiculous.
It really comes down to the perspective we used:
If you start from the basis of Beginners being never evers as L1, and an Expert being WC or Ski Movie Stars as L9.
Then placed everybody else somewhere in middle where would a L1 sit?
Well if you just went off of capability..ie what they can or cant do, they are much closer to Expert then Beginner...about 70% there? So a 7 seems reasonable.
If you went off of percentile..ie what percentile of the skiing population do they sit (WC would be pretty close to 100th percentile, and never evers would be close to 0), I would again but L1 about the 70-75th percentile...so again a L7 designation seems reasonable.
But if you went off of effort...ie after attaining your L1 how much more work is required to hit the WC? Well I am sure in that case most would acknowledge due to the fact that skiing's "effort/ability" curve is steep to start but flattens out as you move up it....(ie, it is easier to improve at the beginning then it is later)...well with this perspective in my view a L1 is only about halfway. Thus L4.
I think it is only natural, that most people would have used one of the first 2 perspectives when assessing if someone is an expert or not...the third perspective would be limited in my view to those that have really worked at their skiing and have experienced the challenge of pushing past the typical L1 skill set...
So anyway armed with that, you can see the difficult in answering the OP:
If L1 or equivalent is expert, then I can safely say I spend 100% of my teaching time dealing with Expert Adults. If you need to be as some suggest a L3, then only about 20%. If you need to be above L3, then the answer drops even further.