frequency of disease development

例句：

1. 1. The frequency of earthquakes in thisregion is relatively high.
   这个地区的地震频率相对较高。
2. 2. The frequency of occurrence of diseasesvaries greatly between different populations.
   不同人群中疾病的发生频率差异很大。
3. 3. The frequency of thedisease is increasing year by year.
   这种疾病的发病率逐年上升。