There's no norm. It depends on what kind of job you do, how closely your desired course is associated with your role, and how your employer sees its position in the employment market. Large and multinational employers are more likely to provide this than small and medium-sized employers. You're much more likely to get assistance with, e.g., training or professional development that is needed to maintain your professional certification than you are with, say, a postgraduate degree in management or business studies.