Table 3.

Follow up in hearing level (dB) at the average of 2, 3 and 4 kHz across the four years of the study period

		2006	2007	2008	2009
Left ear	Firefighter	15.93 ± 12.51	17.08 ± 13.43	16.95 ± 13.79	16.46 ± 14.09
	Factory worker	32.84 ± 14.41	33.21 ± 15.06	31.56 ± 15.98	33.60 ± 17.00
Right ear	Firefighter	15.10 ± 12.72	15.84 ± 13.25	15.95 ± 13.74	15.59 ± 14.15
	Factory worker	29.96 ± 13.48	29.73 ± 14.06	28.40 ± 13.66	30.16 ± 14.46