The Times offers an eye opening view of birth control efficacy over a 10 year period. The male condom has an 86% ten year failure rate with typical (e.g. non-perfect) use. The venerable 'pill' has a 61% failure rate!
It makes a lot of sense when you think about it. If there are 100 couples using a contraception method that has 95% efficacy, that is only 5 failures in the first year. The second year is a cumulative 10 failures, etc. 10 years later, it is 50. That's a 50% ten year failure rate for a 95% effective method.
What an interesting perspective on a common statistic!