I think you’d be surprised at just how few Catholics follow this specific rule! According to the NCHS, 98.8% of sexually experienced Catholic women had used contraception at some point in their lives. (“sexually experienced” in this context means ever had vaginal sex, and the sample size was 10,122 people)

Here’s the direct quote:

Across religious affiliations, 99.7% of women with no religious affiliation, 99.3% of Protestant women, 98.8% of Catholic women, and 97.6% of women affiliated with other religions had ever used a contraceptive method