Table A1-1 Total Domestic Mail Originating in Households and Nonhouseholds Postal Fiscal Years 1987, 2006 and 2007 (Diary Data)
Sector	Percentage of Total Domestic Mail			Pieces Per Household Per Week
	1987	2006	2007	1987	2006	2007
Household-to-household	4.8	3.0	2.7	1.6	1.1	1.0
Household-to-nonhousehold	6.4	6.4	6.7	2.1	2.3	2.3
Nonhousehold-to-household	55.5	70.4	68.8	18.5	24.9	23.9
Unknown incoming	0.3	1.5	1.3	0.1	0.5	0.4
Unknown outgoing	1.0	0.4	0.5	0.3	0.1	0.2
Total Household Mail	69.1	81.7	80.0	23.0	28.9	27.8
Nonhousehold-to-nonhousehold	30.9	18.3	20.0	-	-	-
Total	100.0	100.0	100.0	-	-	-