That is a very difficult subject to study. There have been studies on parties requesting access to justice in both official languages. The last complete study on it was actually done by the Commissioner of Official Languages.
Figures are difficult to obtain because it is a chicken and egg situation. People are not going to ask for something they know is not available. If you don’t know the number of requests or refusals when it comes to hearing a case in French, it is not possible to quantify the problem.