scape percentage (%) character in sp_addmessage

Good Afternoon!

Please forgive my English level.

I'm trying to scape a percentage simbol that I pass as a parameter in a RAISERROR control inside a stored procedured but it seems SQL Server read it as a variable.

My message is defined like this:

EXEC sp_addmessage @msgnum = 60001, @severity = 16,
  @msgtext =
    N'The quota filled with %s and the percentage filled with %s must be mutually exclusive, ie, if one of them is nonzero, the other must be zero.',
   @lang = 'us_english',
   @replace = 'replace';
GO

Then I run a RAISE error inside a stored procedure LIKE THIS:

RAISERROR(60001, -1, -1, N'$1,000,000.00', N'100.00%');

But i obtain the next error message when I execute the stored procedure:

Msg 2787, Level 16, State 1, Procedure pa_1, Line 204

Invalid format specification: '% must be mutually exclusive, ie, if one of them is nonzero, the other must be zero.'.

How can I scape the percentage (%) character inside the especification of the sql server stored procedure sp_addmessage to obtain the desired result

Thanks a lot for your valuable help.