OTTAWA -- When it comes to balancing the country's books, it's the equivalent of finding loose change under a couch cushion.

But each penny surely counts for a Conservative government desperate to press every bit of cash into paying down the deficit.

Federal coffers got a $7-million boost over the last eight years, all without a single tax being raised or any spending being cut.

So what's behind this modest windfall? Long-forgotten bank accounts.

If a bank balance goes untouched for 10 years and no one can find the account owner, the money is transferred to the Bank of Canada.

The central bank holds on to amounts of less than $1,000 for another 30 years, while it keeps amounts above $1,000 for 100 years.

If no one steps forward to claim the money after all that time, the money is transferred to the Receiver General and goes into the consolidated revenue fund. The government can use that money as it sees fit.

Spreadsheet data from the Bank of Canada, released to The Canadian Press under the Access to Information Act, offers a glimpse at the sources of this unlikely manna.

Some accounts date back more than a century, while others are more recent.

The amount of money in the accounts ranges from as little as a penny to almost $1,000.

The account holders come from just about every town and city in Canada, and all over the world.

In 2006, the federal government took in $3.9 million from more than 60,000 dormant accounts.

That number fell sharply the following year after the Conservatives passed legislation that gave people more time to claim their balances.

"Starting in 2007, the time period was extended to 40 years after the last transaction date," Bank of Canada spokeswoman Josianne Menard said in an email.

"As a result, outstanding balances less than $500 will need another 20 years of inactivity before they are transferred to the Receiver General."

The legislation also increased the threshold to $1,000 from $500, she added.

Last year, Ottawa received just under half a million dollars from 661 inactive accounts.

Personal details have been scrubbed from a copy of the list, so it's difficult to learn about the people behind the forgotten dough.

But it's only natural to wonder about their stories.

Like all those people who left just a single penny in the bank. Could they just not be bothered to close their accounts?

Or people who left hundreds of dollars in their accounts more than a century ago. A savvy investor might have made a small fortune over all this time.

Whatever the case, every penny saved -- and then forgotten -- is a penny earned for Ottawa.

While the amounts may be small, there's potentially half a billion dollars up for grabs.

The Bank of Canada says at the end of December, it had about 1.4 million unclaimed balances, worth $532 million, on its books.

The bank adds that it paid out $14 million last year to account holders who came forward to claim their cash.