Sub bullets with numbers

[John Huff]

Is there a way to have a numbered list that sub bullets are an actual sub?  For example, it currently formats in this way

1. Bullet
   1. Sub bullet 1
      1. sub sub 1
      2. sub sub 2
   2. sub bullet 2

I am wanting 

1. Bullet 1

      1.1 Sub bullet 1

            1.1.1 sub sub 1

            1.1.2  sub sub 2

      1.2 sub bullet 2

I use this when I have large lists of requirements as it makes it easy to reference bullet 1.1.2 as opposed to the way it currently formats.