Table 1.

CIT within each time period for 1992–1998 compared to 1999–2002

	1992–1998	1999–2002
00:00–07:29 (P = 0.154)	25.30 (12–38) n = 81	24.10 (12–34) n = 48
07:30–17:59 (P = 0.0001*)	24.00 (10–47) n = 261	19.20 (10–43) n = 168
18:00–23:59 (P = 0.0001*)	23.00 (10–48) n = 197	20.00 (3–42) n = 128

CIT values are in hours, median (minimum–maximum).

P-values (Mann-Whitney U-test) are for the difference in CIT within the same time period before and after 1998.

^*Denotes statistical significance.

n, number of operations.