Figure 1

The distribution of household economic status by county. An asset index was constructed by using principal component analysis (PCA) to classify household economic status. Eleven variables from Section A of the questionnaire were used to calculate the PCA (Appendix A). The first principal component (eigenvalue: 3.315, account for 30.14%) was used to quintile the household economic status (Appendix B). As a result, each household was assigned into one of the five quintiles.