Statements of Assets and Liabilities - USD ($)		Dec. 31, 2018	Dec. 31, 2017
Assets
Cash		$ 10,033,297	$ 41,786,279
Short-term investments(a)	[1]	1,135,484,485	1,303,307,115
Short-term investments held at broker (restricted)(b)	[2]	64,242,167	40,347,527
Receivable for capital Shares sold			3,263,400
Receivable for variation margin on open futures contracts (Note 9)		920,643	5,558,077
Total Assets		1,210,680,592	1,394,262,398
Liabilities
Sponsor’s fees payable		805,937	847,758
Brokerage commissions and fees payable		8,046	5,875
Total Liabilities		813,983	853,633
Commitments and contingent liabilities (Note 7)
Net Assets		$ 1,209,866,609	$ 1,393,408,765
Shares issued and outstanding(c) (in shares)	[3]	86,500,000	85,400,000
Net asset value per Share (Note 2G) (in dollars per share)		$ 13.99	$ 16.32

[1] Cost of short-term investments: $1,135,426,788 and $1,303,324,809, respectively.

[2] Cost of short-term investments held at broker (restricted): $64,238,656 and $40,346,355, respectively.

[3] No par value, unlimited amount authorized.