Table A2-35 First-Class Mail Originating in Households and Nonhouseholds Postal Fiscal Years 1987, 2006 and 2007 (Diary Data)
Sector	Percentage of First-Class Mail			Pieces Per Household Per Week
	1987	2006	2007	1987	2006	2007
Household-to-household	9.1	6.2	5.8	1.6	1.0	0.9
Household-to-nonhousehold	12.2	13.5	14.6	2.1	2.2	2.3
Nonhousehold-to-household	40.6	51.7	53.0	7.0	8.5	8.4
Unknown outgoing	1.9	0.8	1.0	0.3	0.1	0.2
Unknown incoming	0.6	3.0	2.6	0.1	0.5	0.4
Subtotal	64.4	75.3	77.0	11.1	12.4	12.2
Nonhousehold-to-nonhousehold	35.6	24.7	23.0	N/A	N/A	N/A
Total	100.0	100.0	100.0	N/A	N/A	N/A
Base: RPW Total, First-Class Letters & Cards.
Note: Totals may not sum due to rounding.