Table 5.

The proportion of respondents using self-treatment in different self-perceived illness status categories, by year (%)

Variables	1993	1998	2003	2008	χ2
Illness symptoms:
Pain	NA	28.2	35.1	29.1	34.0**
Fever	NA	21.4	25.8	20.8	831.9**
Palpitation	NA	28.0	38.4	26.2	45.3**
Other	NA	33.2	37.5	27.1	298.6**
χ2		328.3**	141.0**	83.6**
Illness severity:
Not serious	NA	34.9	42.5	32.8	148.3**
General	NA	29.3	38.0	27.5	114.3**
Serious	NA	19.5	24.8	20.1	10.7**
χ2		459.2**	497.8**	285.5**
Duration of illness (within 2 weeks):
1-2 days	24.9	34.6	37.9	31.4	48.9**
3-4 days	19.0	28.2	35.3	27.1	28.1**
≥5 days	18.1	25.7	34.7	24.9	12.7**
χ2	148.9**	190.7**(0.000)	21.2**	108.6**
Course of illness:
Acute illness occurred within 2 weeks	NA	27.4	33.3	26.6	773.6**
Acute illness occurred 2 weeks prior	NA	19.6	23.5	17.3	5.2
chronic illness	NA	31.5	39.6	28.4	804.8**
χ2		162.9**	257.3**	133.7**

Source: Author’s calculations from the four CNHS.

NA: no data available.

*Significant at 5%. **Significant at 1%.