Dosage* and years of use	Oral				Transdermal
	N	Observed	Expected	SIR	N	Observed	Expected	SIR
Low
0.5 to five	3,067	28	37	0.75	1,844	24	26	0.94
More than five	2,133	21	18	1.15	739	10	6	1.60
Medium
0.5 to five	408	2	1	1.60	7,006	102	104	0.99
More than five	1,738	20	15	1.38	8,445	104	76	1.32
High
0.5 to five	6,837	88	90	0.98	6,583	98	89	1.10
More than five	9,532	130	87	1.49	1,677	20	14	1.44