You can see that the recent rally in the Dollar has boosted non-dollar investor's returns as the S&P500 has rallied along with the US Dollar. The Dollar is a trade-weighted index, so it doesn't represent anyone's actual returns, but rather a theoretical return on a trade-weighted basis. The largest trading partners with the US weigh heaviest, hence the name.
This year the Dollar Adjusted S&P500 is +15% while the S&P500 is up less than 7% (approximately). The weekly chart (top right) shows the same pattern of outperformance. The 20-year Monthly Chart shows the S&P500 is still beating the Dollar Adjusted Index.
I divided the results by 100 to make the results more readable.
Tim 10:45AM EST 10/6/2014