Update: in the UK Leica film cameras make 6% of total sales (source).
This percentage was given by Leica’s US CEO Roger Horn in an interview with NorthJersey.com:
“Q: What percent of your sales are film cameras?
A: The film cameras are running under 5 percent.”
The second piece of interesting information from this interview: the next Leica store will be open in Willoughby’s camera store in New York City (yes, those are the same guys that were selling M9 on Amazon for a premium more more than once):
“Q: Any plans for one in this area?
A: We will be opening one in Willoughby’s [New York City’s oldest camera store] within another month or so.”