Guessing about the same as the general population, which is less than 2%.
Seems you are quite wrong, as usual, from wiki;
Estimating the number of homosexuals in a given population can be problematic due to problems of measurement, definition, and heterogeneous geographic distribution. Estimates in large populations range from 1% to 15%, with a mean of 4%-5%. (See
Demographics of sexual orientation.) Despite this, evidence from several studies has shown that there are higher than average numbers of homosexual men (active and non-active) within the Catholic priesthood and higher orders.
A number of anonymous studies have suggested a prevalence of homosexual leanings in the Roman Catholic priesthood. Studies by Wolf and Sipe from the early 1990s suggest that the percentage of priests in the Catholic Church who admitted to being gay or were in homosexual relationships was well above the national average for the United States of America.[SUP]
[2][/SUP] Dr
Elizabeth Stuart, a former convener of the Catholic Caucus of the
Lesbian and Gay Christian movement claimed
"It has been estimated that at least 33 per cent of all priests in the RC Church in the United States are homosexual."[SUP]
[3][/SUP]Anecdotal press reports from anonymous sources also suggest that the incidence of
homosexuality in the
Roman Catholic priesthood is much higher than in the general population.[SUP]
[4][/SUP][SUP]
[5][/SUP] It is theorized part of the overrepresentation might be caused by heterosexual priests leaving in order to marry. But it may also have much to do with the Church offering a perceived 'sanctuary' for many men living in societies where homosexuality is criminalised or shunned - especially reducing the pressure by families to marry and have children.
One report suggested that since the mid-1980s Roman Catholic priests in the United States were dying from AIDS-related illnesses at a rate four times higher than that of the general population; with most of the cases contracted through same-sex relations, and the cause often concealed on their death certificates.[SUP]
[6][/SUP] Bishop Thomas Gumbleton of the
Archdiocese of Detroit suggested that: "Gay priests and heterosexual priests didn't know how to handle their sexuality, their sexual drive. And so they would handle it in ways that were not healthy." Furthermore the report suggested that some priests and behavioral experts believe the church had "scared priests into silence by treating homosexual acts as an abomination and the breaking of celibacy vows as shameful".
From Catholic World News,
http://www.catholicculture.org/news/features/index.cfm?recnum=20565
News Feature
[h=2]The Gay Priest Problem June 03, 2002[/h]AIDS has quietly caused the deaths of hundreds of Roman Catholic priests in the United States although other causes may be listed on some of their death certificates, the Kansas City Star reported today. The newspaper said its examination of death certificates and interviews with experts indicates several hundred priests have died of AIDS-related illnesses since the mid-1980s. The death rate of priests from AIDS is at least four times that of the general population, the newspaper said. Kansas City Bishop Raymond Boland says the AIDS deaths show that priests are human.
Even About.com puts the figure at 25%;
http://atheism.about.com/od/catholicismandgays/a/gaypriests_2.htm
This is now a critical juncture for the Roman Catholic Church, particularly in America. Most studies put the number of gay Catholic priests at around 25 percent or higher - dismissing them would devastate an already imperiled American priesthood. The median age of American priests is nearly 60 and getting older. The number of people entering seminaries has dropped by more than 80 percent since 1966, even as the Catholic population in America has increased dramatically.