Student or Learner
Any difference in using "last year" and "past year", when I want to refer to one year ago. Examples below:
"Last year": Following the success of last year's Adult Season
BBC - BBC Three - The Adult Season
"Past year": Pay for the directors of the UK's top businesses rose 50% over the past year.
BBC News - Directors' pay rose 50% in past year, says IDS report
Anthony the learner
'Last year' is the calendar year before the one we are now in, i.e., 2011.
'The past year' is the 12-month period ending yesterday, or very recently,