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FINANCIAL HIGHLIGHTS (Tables) | 3 Months Ended
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Mar. 31, 2019
Financial Highlights [Abstract] |
Per Unit Performance Data and Other Supplemental Financial Data | The following table presents per share performance data and other supplemental financial data for the three months ended March 31, 2019 and 2018 for the shareholders. This information has been derived from information presented in the condensed financial statements.
|  | For the three months ended March 31, 2019 (Unaudited) |  |  | For the three months ended March 31, 2018 (Unaudited) |
Per Share Operating Performance: |  |  |  |  |  |  |  |
Net asset value, beginning of period |  | $ | 17.82 |  |  | $ | 21.05 |
Total income (loss) |  |  | 4.75 |  |  |  | 1.64 |
Total expenses |  |  | (0.05 | ) |  |  | (0.04 | )
Net increase (decrease) in net asset value |  |  | 4.70 |  |  |  | 1.60 |
Net asset value, end of period |  | $ | 22.52 |  |  | $ | 22.65 |
Total Return |  |  | 26.37 | % |  |  | 7.60 | %
Ratios to Average Net Assets |  |  |  |  |  |  |  |
Total income (loss) |  |  | 22.55 | % |  |  | 7.71 | %
Management fees* |  |  | 0.60 | % |  |  | 0.60 | %
Expenses excluding management fees* |  |  | 0.31 | % |  |  | 0.21 | %
Net income (loss) |  |  | 22.32 | % |  |  | 7.51 | %
* | Annualized.

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