The second sentence “You must declare…” is also used in circumstances like filing an income tax return, in which case it refers to the contained taxation period, again, usually January-December.

Many companies have fiscal years that are shifted from the calendar year. My company’s fiscal year runs April-March, so for us, “in the past year,” in a financial report would mean the last April-March period.

On a personal basis, “the past year” usually means the past 12 month period. If I said, “The past year has been really difficult for me,” that would mean from a year ago to today.

If I said, “Last year was really difficult for me,” that would mean Jan-December 2006.

It’s confusing, and depends a lot on context.

>Real incomes have gone up by 10% in the past year.

>You must declare all you have earned in the last year.

>The company has announced heavy losses in the last year.

All these refer to the financial report of a company. In the context , it always means the previous financial year of the company. In general, financial year of a company in the US is Jan-Dec. In that case, if the referred report is released in 2007, the company is referring to it’s previous financial year Jan 2006 to Dec 2006.