vacancy concentration

例句：

1. 1.The vacancy concentration in the market has increased significantly.
   市场的空位浓度显著增加。
2. 2. The company is trying to reduce its vacancy concentration by hiring more staff.
   该公司正试图通过招聘更多员工来降低其空位浓度。
3. 3.The researcher found that the vacancy concentration in the region had a significant impact on the economy.
   研究人员发现该地区的空位浓度对经济产生了重大影响。