Based on the 2010 application spreadsheet of which I was an administrator, it was 2.5%.
That means multiply any given NOC applicant rate by 40 to get an approximate worldwide total. For the 2013 applicants it does not follow that it will be exactly the same, but certainly somewhere between 2% and 5% would be realistic.
Interestingly if we apply the x40 factor to the current NOCs on the 2013 spreadsheet we get these figures:
Forum apps World total (guess)
46 1840 Computer programmers and interactive media developers
41 1640 Financial and investment analysts
26 1040 Computer engineers (except software engineers/designers)
12 480 Civil engineers
7 280 Inspectors in public and environmental health and occupational health and safety
4 160 Physiotherapists
7 280 Mechanical engineers
2 80 Medical Radiation Technologists
8 320 Engineering managers
1 40 Geoscientists and oceanographers
2 80 Land surveyors
1 40 Medical laboratory technologists
1 40 Medical Sonographers
1 40 Petroleum engineers
0 0 Chemical engineers
0 0 Mining engineers
0 0 Geological engineers
0 0 Aerospace engineers
1 40 Industrial instrument technicians and mechanics
0 0 Audiologists and speech-language pathologists
0 0 Occupational Therapists
2 80 Medical laboratory technicians and pathologists' assistants
0 0 Respiratory therapists, clinical perfusionists and cardiopulmonary technologists
0 0 Cardiology technologists and electrophysiological diagnostic technologists
Rows in red are (according to the formula!) already full, and those in orange are very close. Of course that's not quite true because a few of those on the spreadsheet may not have sent their apps yet, or apps may be in transit.
But this is an approximation only.
Wayne.