In the 2005 elections, Angela Merkel became the first female chancellor. In 2009 the German government approved a €50 billion stimulus plan. Among the major German political projects of the early 21st century are the advancement of European integration, the energy transition () for a sustainable energy supply, the "Debt Brake" for balanced budgets, measures to increase the fertility rate (pronatalism), and high-tech strategies for the transition of the German economy, summarised as Industry 4.0. Germany was affected by the European migrant crisis in 2015: the country took in over a million migrants and developed a quota system which redistributed migrants around its states.