I have a DataFrame such as this: 

```
Index Label
0     ABCD
1     EFGH
2     ABCD
3     ABCD
4     EFGH
5     ABCD
6     IJKL
7     IJKL
8     ABCD
9     EFGH

```

So, "ABCD" occurs 5 times, "EFGH" 3 times and "IJKL" twice. I want to count the occurence of each Label and replace the individual labels with their count, to get the following: 

```
Index Label
0     5
1     3
2     5
3     5
4     3
5     5
6     2
7     2
8     5
9     3

```

What is the nicest way to do this?
Thank you!