The actual date that the world population reached 7 billion had an error margin of around 12 months owing to inaccuracies in demographic statistics, particularly in some developing countries (even the world's best censuses have 1–2% error).[citation needed] Assuming a 1% global error margin, the 7 billion world population could have been reached as early as March 20, 2011 or as late as April 12, 2012.[9]