Vim – Incrementing a column of numbers

Whenever I’m mocking up a sample web page, I inevitably end up doing something like this; Create a line; <li id="1">This is item 1</li> Copy it a bunch of times; <li id="1">This is item 1</li> <li id="1">This is item 1</li> <li id="1">This is item 1</li> <li id="1">This is item 1</li> <li id="1">This is item 1</li> …