I am trying to convert the values in a Pandas DataFrame from string to float but am running into an error.

The column looks like this:

```none
PIB (IBGE/2005)
---------------
 71.638.000
114.250.000
 44.373.000
462.258.000
186.812.000

```

Where the `.` are the digit group separators, so `71.638.000` should become the float `71638000`.

But I am getting the error:

```none
ValueError: could not convert string to float: '71.638.000'

```

Here is an image of my full DataFrame:

![Dataframe screenshot](https://i.stack.imgur.com/uuWT1.png)
How can I convert this column from string to float?