First of all, this "guesstimate" is for the United States. Second, we have to be careful how we define "homophobia." A phobia is an irrational fear, so homophobia is an irrational fear of homosexuality. Some people don't like homosexuals because they haven't met one, or because someone has told them things that aren't true. So these people do not technically have homophobia.
Probably somewhere around 50% of people are ignorant or deceived about homosexuals. But I would guess that no more than one person out of five (20%) has an irrational fear of homosexuals.
Homophobic or homophobia
A tiny fraction of adults are homophobic - irrationally afraid of homosexuals. Their homophobia has little effect on homosexuals or on themselves.
Racism is the judgment of someone based solely on their race, and homophobia is when someone is scared of becoming gay or gay people.
Discrimination is discrimination in any form.
AARGH - Artists Against Rampant Government Homophobia - has 76 pages.
Education is good. But the best treatment for homophobia is personally knowing a gay person. That's why gay people should not disown homophobic friends.
Homophobia
It is called homophobia.
There is no such word as omophobia. Assuming that you mean homophobia, it is the dislike of homosexual people.
Sadly Homophobia exists in all countries on the planet.
If fear of gays is homophobia, then fear of straight people would be heterophobia.
74,000 people