Smoking and the business cycle : evidence from Germany / Micha Kaiser (University of Hohenheim), Mirjam Reutter (University of Hohenheim), Alfonso Sousa-Poza (University of Hohenheim and IZA), Kristina Strohmaier (Ruhr University Bochum and University of Hohenheim) ; IZA Institute of Labor Economics. Bonn, Germany : IZA Institute of Labor Economics, August 2017