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v3.19.1

FINANCIAL HIGHLIGHTS (Per Unit Performance Data and Other Supplemental Financial Data) (Details) - $ / shares | 3 Months Ended
--- | ---
Mar. 31, 2019 | Mar. 31, 2018
Per Share Operating Performance: |  |  |  |
Net asset value, beginning of period |  | $ 24.35 | $ 23.34 | [1]
Total income (loss) |  | (0.85) | (0.73) |
Total expenses |  | (0.08) | (0.07) |
Net increase (decrease) in net asset value |  | (0.93) | (0.80) |
Net asset value, end of period |  | $ 23.42 | $ 22.54 |
Total Return |  | (3.82%) | (3.43%) |
Ratios to Average Net Assets |  |  |  |
Total income (loss) |  | 0.11% | 2.85% |
Management fees | [2] | 0.60% | 0.60% |
Expenses excluding management fees | [2] | 0.78% | 0.70% |
Net income (loss) |  | (0.23%) | 2.53% |
[1] | On January 4, 2018, there was a 1-for-4 reverse share split. Historical shares outstanding, net asset value per share and market value per share have been adjusted for the period shown to reflect the 1-for-4 reverse share split on a retroactive basis.
[2] | Annualized.

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