10/02/2014 05:26 EDT | Updated 12/02/2014 05:59 EST

Last year's deficit lower than expected, but target moves over time

OTTAWA - Prime Minister Stephen Harper says the budget for the 2013-14 fiscal year will be $5.2 billion, well below the $16.6 billion forecast in the last budget last February.

But forecasting is more murky art than exact science and a target missed by $10 billion or so isn't unusual. The 2013-14 deficit number, in fact, has bobbed up and down over three consecutive budgets.

The 2012 budget predicted a shortfall of $10.2 billion for 2013-14.

The 2013 budget upped that prediction to $18.7 billion.

The 2014 budget dropped it to $16.6 billion.

In similar fashion, the deficit for 2012-13, was forecast to be $21.1 billion in the 2012 budget.

By the next year, it was up to $25.9 billion. In fact, the actual deficit for 2012-13 was $18.9 billion.