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FINANCIAL HIGHLIGHTS (Details) (USD $) | 3 Months Ended |
--- | --- | ---
Mar. 31, 2013 | Mar. 31, 2012 | Jun. 02, 2010
Per Unit Operating Performance: |  |  |  |  |
Net asset value, beginning of period | $ 81.95 |  | $ 74.54 |  | $ 50.00
Total income (loss) | $ 1.52 |  | $ 11.96 |  |
Total expenses | $ (0.21) |  | $ (0.20) |  |
Net increase in net asset value | $ 1.31 |  | $ 11.76 |  |
Net asset value, end of period | $ 83.26 |  | $ 86.30 |  | $ 50.00
Total Return | 1.60% |  | 15.78% |  |
Ratios to Average Net Assets |  |  |  |  |
Total income (loss) | 1.81% |  | 13.30% |  |
Management fees | 0.75% | [1] | 0.75% | [1] |
Total expenses excluding management fees | 0.39% | [1] | 0.29% | [1] |
Expenses waived | (0.14%) | [1] | (0.06%) | [1] |
Net expenses excluding management fees | 0.25% | [1] | 0.23% | [1] |
Net income (loss) | 1.57% |  | 13.05% |  |
[1] | Annualized

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