A 10 year timeframe is nothing. Sometimes International wins, and sometimes Domestic wins. It all depends on when you're looking. Had you sat down in January 2014 and ran the numbers, you'd see International ahead since 1971! 43 years of International outperformance!
Instead you're looking at it today, just when Domestic crossed over and started winning:
It all depends on your timeline - when you're looking. You can't predict which country will outperform in the future, just like you can't predict which stock will outperform in the future. Heck, you can't even predict your own personal timeline! The only way to win this game, is to not play. Market-weight, currently 54/46 USA/International, is the only thing that makes sense.
Looking at some 30+ year time periods for International:
The money you invested in Jan 1971 - has made 10% a year
The money you invested in Jan 1972 - has made 9% a year
The money you invested in Jan 1973 - has made 10% a year
The money you invested in Jan 1974 - has made 11% a year
The money you invested in Jan 1975 - has made 10% a year
The money you invested in Jan 1976 - has made 10% a year
The money you invested in Jan 1977 - has made 10% a year
The money you invested in Jan 1978 - has made 9% a year
The money you invested in Jan 1979 - has made 10% a year
The money you invested in Jan 1980 - has made 9% a year
The money you invested in Jan 1981 - has made 10% a year
The money you invested in Jan 1982 - has made 10% a year
The money you invested in Jan 1983 - has made 9% a year
The money you invested in Jan 1984 - has made 10% a year
The money you invested in Jan 1985 - has made 8% a year
I'm not sure what you're expecting out of the stock market. Those are some pretty good numbers.