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FINANCIAL HIGHLIGHTS | 12 Months Ended
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Dec. 31, 2018
Financial Highlights [Abstract] |
Financial Highlights | NOTE 6 — FINANCIAL HIGHLIGHTS The following table presents per share performance data and other supplemental financial data for the years ended December 31, 2018, 2017 and 2016 for the shareholders. This information has been derived from information presented in the financial statements.
|  | Year ended December 31, 2018 |  |  | Year ended December 31, 2017 |  |  | Year ended December 31, 2016 |
Per Share Operating Performance: |  |  |  |  |  |  |  |  |  |  |  |
Net asset value, beginning of year |  | $ | 21.05 |  |  | $ | 20.39 |  |  | $ | 17.00 |
Total income (loss) |  |  | (3.04 | ) |  |  | 0.82 |  |  |  | 3.52 |
Total expenses |  |  | (0.19 | ) |  |  | (0.16 | ) |  |  | (0.13 | )
Net increase (decrease) in net asset value |  |  | (3.23 | ) |  |  | 0.66 |  |  |  | 3.39 |
Net asset value, end of year |  | $ | 17.82 |  |  | $ | 21.05 |  |  | $ | 20.39 |
Total Return |  |  | (15.34 | )% |  |  | 3.24 | % |  |  | 19.94 | %
Ratios to Average Net Assets |  |  |  |  |  |  |  |  |  |  |  |
Total income (loss) |  |  | (6.16 | )% |  |  | 2.46 | % |  |  | 27.09 | %
Management fees |  |  | 0.60 | % |  |  | 0.60 | % |  |  | 0.60 | %
Expenses excluding management fees |  |  | 0.22 | % |  |  | 0.26 | % |  |  | 0.12 | %
Net income (loss) |  |  | (6.98 | )% |  |  | 1.60 | % |  |  | 26.36 | %
Total returns are calculated based on the change in value during the period. An individual shareholder’s total return and ratio may vary from the above total returns and ratios based on the timing of contributions to and withdrawals from USL.

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