Regular Expressions

I have this code:

$text='Regular Expressions in PowerShell: KB987654, KB987111, KB987999, KB987222 Get all KB numbers.'
$pattern='KB(\d{4,6})'
$text-match$pattern
$matches

when I run this it returns the following.

Name Value
---------
1 987654
0 KB987654

It only returns the First KB number and it returns it twice.  How do I make this return all 4 KB numbers?

Thanks.