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FINANCIAL HIGHLIGHTS (Details) - $ / shares | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Per Share Operating Performance: |  |  |
Net asset value, beginning of period | $ 17.23 | $ 22.95 | $ 17.82
Total income (loss) | 10.79 | (5.59) | 5.32
Total expenses | (0.21) | (0.13) | (0.19)
Net increase (decrease) in net asset value | 10.58 | (5.72) | 5.13
Net asset value, end of period | $ 27.81 | $ 17.23 | $ 22.95
Total Return | 61.40% | (24.92%) | 28.79%
Ratios to Average Net Assets |  |  |
Total income (loss) | 53.01% | 61.24% | 26.56%
Management fees | 0.60% | 0.60% | 0.60%
Total expenses excluding management fees | 0.30% | 0.28% | 0.28%
Net income (loss) | 52.11% | 60.36% | 25.68%

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