1. Physicians" are ASCO (Australian Standard Classification of Occupations) code 231 and;Australia;Physician and professional nurse stocks are from Australian Bureau of Statistics "data available upon request,2001
2. Professional nurse stocks from Enqu�te Socio-�conomique;Service Publique F�d�ral d'�conomie, PME, Classes Moyennes et �nergie: Direction G�n�rale de la Statistique et de l'Information �conomique,2001
3. Physicians" are NOCS (National Occupational Classification for Statistics) codes D011 and D012, and;Canada;Statistics Canada table "Labour Force 15 Years and Over by Occupation,2001