如何从数据子集计算百分比

Question

我有这个数据集：

City <- c("New York", "New York", "New York", "New York", "New York", 
          "Dallas", "Dallas","Dallas","Dallas","Dallas")
Income <- c("1","2","3","4","5","1","2","3","4","5")
Amount <- c(0, 13291.23678, 0,0,0,0, 65666.2885,106896.3682,69949.63342,35549.94405)

DF <- data.frame(City, Income, Amount)

我想计算每个城市的“金额”百分比。我的预期结果是：

       City Income    Amount Amount_Percentage
   New York      1      0.00   0.00%
   New York      2  13291.24 100.00%
   New York      3      0.00   0.00%
   New York      4      0.00   0.00%
   New York      5      0.00   0.00%
     Dallas      1      0.00   0.00%
     Dallas      2  65666.29  23,62%
     Dallas      3 106896.37  38,44%
     Dallas      4  69949.63  25,16%
     Dallas      5  35549.94  12,78%

非常感谢您的帮助。

问候！