The most exhaustive analysis on this question was performed by Philip Jenkins in his book Pedophiles and Priests: Anatomy of a Contemporary Crisis. Jenkins conclusions, in a nutshell, is that Catholic priests do not commit sexual abuse against minors at a rate higher than other faiths or occupations, and in fact may have rates of sexual abuse less than that of many or most other professions, that the incidence of "pedophilia", i.e., sexual relations with pre-pubescent child, as compared with "ebophilia," sexual relations with post-adolescent teenagers, is extremely small, and that the popular perception of pedophilia and Catholic priests owes much to deeply imbedded historical, American anti-Catholic prejudice and a confluence of sociological factors, including the breakdown of Catholicism as a key identity of Catholics and the fact that because of its structure, the Catholic Church has "deep pockets" that make it an attractive "target" for suits.
Jenkins' study was performed in the late '90s, but its conclusions have held up over time. The recent John Jay College Report on the Causes and Context of Sexual Abuse of Minors by Catholic Priests in the United States, 1950 - 2010, published in May of 2011, confirms that the number of priests accused of child abuse was around 4% of the total number of priests, that the number of priests who were true pedophiles was around 5% of priests acccused of child abuse, and that the incidence of child abuse peaked around 1970 and has fallen since that time. [One should also be aware that not all "child abuse" allegations involve allegations of physical impropriety.]