Politicians and the convenience of round numbers

What is it about politicians and round numbers? Queensland Premier Anna Bligh committed to creating 100,000 new jobs over three years at Labor's official campaign launch today.

In the last few months, this 100,000 job creation figure has been used elsewhere.

In the UK:

Gordon Brown: I'll create extra 100,000 jobs, by Alastair Jamieson, Telegraph, 22 December 2008. Government spending programmes brought forward to soften the effects of the economic crisis will provide at least 100,000 jobs, Gordon Brown said.

And the US:

Salazar Says Interior Stimulus to Create 100,000 Jobs, by Daniel Whitten, Bloomberg, 20 February 2008. U.S. Interior Secretary Ken Salazar said a department “stimulus czar” and task force will help direct the spending of about $3 billion in economic-recovery funds, which may create 100,000 jobs.