I have a dataframe, `df` that looks this way:

```
Year Colombia    Chile
------------------------
2006   9.5660    24.5576
2007  26.0079    10.9652
2008  16.0893    2.3721
2009  -5.1036   -5.0465

```

And I want to add two columns called `index_Colombia` and `index_Chile` so that in the first row `f(1)` the value is 100 and the value of the second row for `Colombia` is 100\*(1+26.0079/100) and for Chile 100\*(1+10.9652/100), and so on... so that we get the following df

```
Year Colombia    Chile    index_Colombia   index_Chile 
-------------------------------------------------------
2006   9.5660    24.5576      100            100       
2007  26.0079    10.9652   126.0079         110.9652
2008  16.0893    2.3721     146.2816         113.5974
2009  -5.1036   -5.0465     138.8159        107.864

```

it occurs to me that it is necessary to do with the `mutate` function but I do not know how to formulate it.... Can you help me?