European stock mutual funds’ decline last year wreaked havoc on their 10-year returns relative to the S&P 500. But several European mutual funds have managed to keep pace with the U.S. stock benchmark, helped by this year’s rally. If you’d invested $10,000 in the average European fund on June 30, 2000, you’d have $18,016 sitting in your account as of July 24 this year, according to Morningstar Inc. data.