Colorectal cancer in Guangdong Province of China: A demographic and anatomic survey

Table 4 Mean age and year group in different areas

Yr	n	mean age (yr)	≤30 yr	31-40 yr	41-50 yr	51-60 yr	61-70 yr	≥71 yr	Male:female
1986-1988	462	52	37	62	101	153	82	47	1.7:1
1989-1991	532	55	41	69	104	159	125	34	1.7:1
1992-1994	866	56	56	116	158	251	208	77	1.6:1
1995-1997	1103	58	68	133	183	270	341	108	1.3:1
1998-2000	1523	59	85	138	267	358	447	228	1.5:1
2001-2003	1793	60	99	174	275	379	520	346	1.4:1
2004-2006	1893	60	113	177	273	407	548	375	1.5:1
	3.11	82	2.11	2.91	1.71	1.71	5.71	7.01	3

¹Increasing fold;

²Increasing years of mean age;

³χ² = 12.703, P = 0.013, the difference was significant.