I am having data as below

```
**Heading    Date**
A          2009-02-01
B          2009-02-03
c          2009-02-05
d          2009-02-06
e          2009-02-08

```

I need rank as below

```
Heading    Date           Rank
A          2009-02-01      1
B          2009-02-03      2
c          2009-02-05      1
d          2009-02-06      2
e          2009-02-07      3

```

As I need rank based on date. If the date is continuous the rank should be 1, 2, 3 etc. If there is any break on dates I need to start over with 1, 2, ...

Can any one help me on this?