Commitment periods define a certain period of time during which certain targets have to be met. Under the Kyoto Protocol, Annex I Parties committed to reduce GHG emissions to an average of five percent against 1990 levels over the first commitment period (1 January 2008 to 31 December 2012). As of March 2015, the Doha Amendment establishing the second commitment period of the Kyoto Protocol has been ratified by 26 countries.