Note 8 - Financial Highlights (Tables)

12 Months Ended

Dec. 31, 2021

Notes Tables

Financial Highlights [Table Text Block]

	December 31,
	2021(a)			2020(a)			2019(a)
Net asset value per Share, beginning of year	$	36.06		$	29.12		$	24.56
Net investment loss(b)		(0.09	)		(0.08	)		(0.06	)
Net realized and unrealized gain (loss)(c)		(1.35	)		7.02			4.62
Net increase (decrease) in net assets from operations		(1.44	)		6.94			4.56
Net asset value per Share, end of year	$	34.62		$	36.06		$	29.12
Total return, at net asset value(d)		(3.99	)%		23.83	%		18.57	%
Ratio to average net assets:
Net investment loss		(0.25	)%		(0.25	)%		(0.25	)%
Expenses		0.25	%		0.25	%		0.25	%