Reports Developer (Running Number)

hi,
i’m using Reports Developer ver60 in oracle. i’m running a tabular type of report and i want to number my report on the side e.g. 1 2 3 4 5 …my layout example below..
name address
1 xxxxxxxxxx xxxxxxxxxxxx
2 xxxxxxxxx xxxxxxxxxxxx
3 xxxxxxxxxx xxxxxxxxxxxx
4 xxxxxxxxxx xxxxxxxxxxxx
5 xxxxxxxxxx xxxxxxxxxxxx