Typical size of Training Dept.

I recently started a new job with a large health care company to assess IT training requirements. My immediate plan is to meet with IT management to assess training needs and priorities. Additionally I will need to determine how the training curriculum should be offered to satisfy the established needs.

I would be very interested to know if any guidelines, metrics or statistics exists to gauge the appropriate size of a corporate training department to support an IT division with 850 employees. How many trainers are needed and what considerations should be factored in determining that number?