Taken from the Health Canada webpage:
http://www.hc-sc.gc.ca/hl-vs/iyh-vsv/diseases-maladies/hiv-vih-eng.php#hivc
" The Public Health Agency of Canada (PHAC) estimates that approximately 65,000 people were living with HIV infection in Canada at the end of 2008...
...According to Summary: Estimates of HIV Prevalence and Incidence in Canada, 2008, men who have sex with men continue to be the group most affected by HIV/AIDS in Canada. Estimates were classified according to the following exposure categories for new infections:
•44% were men who have sex with men;
•17% were people who use injection drugs;
•3% were men who have sex with men and use injection drugs;
•36% were heterosexuals.
At the end of 2008, women living with HIV accounted for approximately 22% of the national total. Aboriginal peoples account for a disproportionately high percentage of the individuals living with HIV infection in Canada. Although Aboriginal peoples represented only 3.8% of the Canadian population in the 2006 census, they accounted for approximately 7.4% of individuals living with HIV and for 12.5% of those who were newly infected."
Statistics splits amongst those infected:
47% gay men / 22% women / 31% hetero men
17% injection users - 3% gay injection users = 14% are injection users who are not gay men, thus:
14% x (22%/(22%+31%) = 14% x 41.51% = 5.81% are female injection users (assuming male/female split provided*)
14% x (31%/(22%+31%) = 14% x 58.5% = 8.19% are hetero male injection users (assuming male/female split provided*)
(*my assumption of a 50/50 weighted split between male/female injection users probably is skewed. It just seems through life experience that a majority of injection users are probably going to be weighted heavily on the male side. If this is the case, then the final calculations found later for both males and females who are not IV drug users would need adjusting)
Therefore, if 22% of HIV carriers are female,
22% - 5.81% female injection users = 16.19% are females who do not use injection drugs
78% - 47% - 8.19% = 22.81% are hetero males who do not use injection drugs
% of all people (male/female) in Canada with HIV: 65,000/32,000,000 = 0.203% (<1%, or approx 1 in 500) of the entire population;
% of males in Canada with HIV: 78% x 0.203% = 0.158% (1 in 650 people, or approx 1 in 325 males assuming 50/50 male/female split)
% of females in Canada with HIV: 22% x 0.203% = 0.044% (1 in 2,250 people, or approx 1 in 1,125 females assuming 50/50 male/female split)
% of straight males who do not use IV drugs in Canada with HIV: 22.81% x 0.203% = 0.046% (approx 1 in 2,175 people, or 1 in 1,088 males assuming 50/50 male/female split)
% of females who do not use IV drugs in Canada with HIV: 16.19% x 0.203% = 0.033% (approx 1 in 3,000 people, or 1 in 1,500 females assuming 50/50 male/female split)
So, if I manage to stay away from having sex with a gay man or any IV drug users, then if I'm lucky enough to have sex with approximately 1,500 women, then statistically one of them should have HIV.
I would imagine I'll be able to stay away from anyone who clearly uses, or who clearly has HIV.
And what is the probability of the disease being transferred in that 1 out of 1,500 unfortunate encounter?