As of November 2016, the CMS collaboration has over 5000 active people (physicists, engineers, technical, administrative, students, etc.) [ latest details & plots ]

Of these members there are about:

• 1966 PhD physicists (1639 men, 327 women) [ latest details & plots ]
• 927 physics doctoral students (722 men, 205 women) [ latest details & plots ]
• 998 engineers (880 men, 118 women) [ latest details & plots ]
• 1004 undergraduates (762 men, 242 women) [ latest details & plots ]

(the above categories are, by definition, non-overlapping)

A typical CMS physics paper will be signed by the PhD physicists and a significant fraction of the doctoral students meaning it will typically have over 2000 signatories.