Table 1

Comparison of response rates between examinations

Examination year (response rate, %)P value (2000)P value (2005)P value (2009)P value (2015)P value (2018)
2000 (69.5)0.013<0.0000.003<0.000
2005 (64.1)0.1510.381<0.000
2009 (61.1)0.690<0.000
2015 (62.0)<0.000
2018 (51.2)
  • Statistical analysis: to test differences between groups, χ2 test was used.