Table 11. Percent distribution of observed frames among postural risk classes by operation.

Category		AC1(%)	AC2(%)	AC3(%)	AC4(%)	PRI
Site 1	Worker1	46.3	14.4	26.6	12.7	205.7
	Worker2	57.9	16.4	22.0	3.7	171.5
	Worker3	48.8	16.0	29.5	5.7	192.1
	Worker4	44.0	13.1	35.6	7.4	206.6
	Mean	49.3	15.0	28.4	7.4	194.0
Site 2	Worker5	46.6	18.7	30.9	3.7	191.5
	Worker6	49.6	25.9	22.2	2.2	176.8
	Worker7	66.0	16.6	16.2	1.2	152.6
	Mean	54.1	20.4	23.1	2.4	173.6
Site 3	Worker8	64.6	23.2	6.1	6.1	153.7
	Worker9	64.3	28.0	1.3	6.4	149.8
	Worker10	68.4	18.6	9.1	4.0	148.9
	Worker11	68.4	18.4	7.9	5.3	150.1
	Mean	66.4	22.1	6.1	5.5	150.6
Site 4	Worker12	51.8	18.3	17.0	12.8	190.6
	Worker13	52.5	29.7	12.0	5.7	170.7
	Worker14	43.2	35.5	17.4	3.9	182.0
	Mean	49.2	27.8	15.5	7.5	181.1
Site 5	Worker15	44.2	17.0	28.9	10.9	208.5
	Worker16	45.1	22.6	21.5	10.8	198.0
	Worker17	51.4	21.9	17.1	9.5	184.5
	Mean	46.9	20.5	22.5	10.4	197.0
Grand mean		53.7	20.8	18.9	6.6	178.4