U.S. rental libraries about 1935

	A	B	C	D	E	F
1	Estimating circulation of U.S. rental libraries in 1935
2	Douglas Galbi		http://purplemotes.net
3	For discussion of these data, see		http://purplemotes.net/2009/05/03/circulation-from-rental-and-public-libraries/
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6	Parameters	Census	Scenario 1	Scenario 2	Scenario 3	source note
7	ave. book rental revenue per year per rental library	2,966	1,500	2,966	4,000	Census data; model income statement
8	ave. rental cost	$0.25	$0.25	$0.25	$0.20	see, e.g. Conklin (1934) p. 56
9	# of rental libraries	932	20,000	20,000	40,000	see blog post
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11	Estimate
12	steady-state rental circulation per year	11,057,248	120,000,000	237,280,000	800,000,000
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15	Additional parameters
16	rental book purchase cost as share of rental revenue	50%	50%	50%	50%	see model income statement sheet
17	wholesale cost per book	1.45	1.45	1.45	1.45	see model income statement sheet
18	rentals per book	20	20	20	20	30 rentals per book (Conklin (1934) p. 93; calculated 28, 19: see model income statement; 28, Publisher's Weekly 1934 and "Book Notes," New York Times, June 1, 1934, p. 21.
19	ave book rental life in years	0.5	0.5	0.5	0.5	estimate
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21	Additional estimates
22	number of books purchased per rental library per year	1,023	517	1,023	1,379
23	steady-state library size	511	259	511	690
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25						Publisher's Weekly. 1934. “Borrowers are 6 to 1?” June 9, pp. 21-42.
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