Column Help

I have created a spread sheet in excel and over the years it's gotten pretty big. I have a column called ID that has numbers in it. Over the the years some of those numbers in the id column have been removed.

For example, the current spread sheet looks like something like this

1
1
2
5
16
16
16
16
28
28
28
28
40
40
40
45
50
60
60
60

What I want to do is to make the column where numbers are not missing between other numbers including keeping the duplicate numbers.

For example

1
1
2
5
16
16
16

I like for those numbers to now look like

1
1
2
3 ( is 5)
4 (is 16)
4 (is 16)
4 (is 16)

Is this possible to get this done in excel? Hopefully I am not confusing anyone on what I am trying to accomplish here.

Thanks,
RedKobra