Excel 2007 : How to create a repeat set of sequence number index where values appear in a row

Hi,

It's hard to explain what I want to achieve so I apologise if I confuse you here. I've included a sample excel (attached) and highlighted what I want to achieve in red.

I have a set of data in excel and I want to insert a new column A to contain a numeric index but I would like the numbers to repeat if that row contains any values, otherwise, if the row is completely empty, then that row index is blank or has a symbol/zero (doesn't matter). The next row containing values, the index would then contain the next number.

That was terrible, sorry. Here's another example of what i'm trying to achieve:

A B C D
1 word word
1 word word
1 word
1 word
1 word
*
2 word word
2 word word
2 word
2 word
2 word
*
3 word word
3 word word
3 word
3 word
3 word


Hope that helps.
Thanks!