Table 4. Pigs at weaning growing rate and ages at weaning (unit: pigs, %, days)

Year\Traits	No.of weaning	Growing rate	Ages at weaning
	Mean ± S.D	Mean ± S.D	Mean ± S.D
1970	8.04 ± 1.21	77.85 ± 2.04	45.25 ± 4.50
1980	8.21 ± 1.42	79.01 ± 1.95	42.31 ± 2.78
1990	8.42 ± 1.35	80.22 ± 1.94	40.25 ± 2.24
2000 (A)	8.65 ± 1.65	88.41 ± 1.93	35.24 ± 2.52
2010	9.16 ± 1.74	90.25 ± 1.85	26.95 ± 2.46
2018 (B)	9.85 ± 1.20	94.30 ± 2.24	24.22 ± 2.59
Average	8.72 ± 1.43	85.01 ± 1.99	35.70 ± 2.85
B/A (%)	13.87	6.66	—31.28