panic disorder,a type of anxiety in which people experience

panic disorder,a type of anxiety in which people experience feelings of panic,affects eight out of every thousand people.
Five to 10 percent of Americans suffer from phobias,a type of anxiety in which people experience intense fear of things such as spiders,dogs,orbridges.
可以帮我翻译这些句子吗,还有可以告诉我in which在这里是什么用法吗．

恐慌症,是一种人们感到惊慌的焦虑现象,在1000个人当中,就有8个人有这个症状.
5至10八仙的美国人都有恐惧症,是一种人们对某种事物如蜘蛛,狗又或者桥,感到十分害怕的焦虑现象.
in which 在这里用于进一步提供相关事物的信息,而这里的in which就是对anxiety多加于解释补充.