12 in Web Appx. Section A.3, this issue only affects a few older individuals in the earliest surveys of 12 countries. Using returns based on the 0-25 bins, as we estimate later, also eliminates the issue. Finally, results hold if we exclude the 12 countries or exclude only the problematic surveys that number 12 in total and involve 7 countries.<sup>17</sup> An alternative approach is to construct for each country periods based on important years, e.g. for the United States, 1923-1928, 1929-1932, 1933-1940, 1941-1944, 19451953, 1954-1961, 1962-1963, 1964-1967, 1968-1973, 1974-1979, 1980-1989, 1990-1993 and 1994-2000, due to important events in 1929 (Great Depression), 1933 (New Deal), 1941 (Pearl Harbor), 1945 (World War II ends), 1954 (ends of racial segregation in schools), 1962 (Cuban Missile Crisis), 1964 (Civil Rights Act), 1968 (Martin Luther King assassinated), 1974 (Watergate), 1980 (Reagan), 1990 (Gulf War starts, Cold War ends), 1994 (NAFTA), 2001 (9-11), and 2007 (Great Recession).<sup>18</sup> We identify important events using information from standard sources such as Wikipedia. For each country, we read the top of the Wikipedia webpage of the country (in English as well as in the main language of the country) as well as the “contemporary/modern period” and “colonial period” sections.<sup>19</sup> We cross-check this information using other sources, e.g. the BBC Profile of each country.<sup>20</sup> We then include in the regressions estimating the returns country-specific period dummies equal to one if the individual was aged between 18 and 67 during the period(s), for countries with at least two years of data. Doing so captures the fact that each person was affected by multiple events during her lifetime. For example, an American person born in 1931 was 18 in 1949 and 67 in 1998. For her, the 1945-1953, 1954-1961, ..., 1990-1993 and 1994-2000 period dummies are equal to one. Of course, blindly following Wikipedia-BBC may lead us to include events that might not be that “important” for workers. At the same time, it is better if we 17Web Appx. Section A.3 and Web Appx. Table A.8 show that effects do not vary much if we increase the number of years of data required for a country to be considered or use 20-year cohort fixed effects. The 5- year cohort fixed effects preserve the difference between developed and developing countries. However, returns are lower across all countries, since collinearity increases as one uses more refined cohort fixed effects.

> 18For Kenya: 1920 (Crown Colony), 1940 (Italian attack), 1944 (Kenyan African Union), 1947 (Kenyatta becomes KAU leader), 1952 (Mau Mau rebellion), 1956 (rebellion ends), 1960 (state of emergency ends), 1963 (Independence), 1969 (Mboya assassinated), 1978 (Kenyatta dies, rule of Moi), 1982 (one-party state), 1987 (opposition suppressed), 1992 (elections, conflict), 1996 (constitution amended), 2002 (Moi’s reign ends), 2007 (electoral violence), 2010 (constitution, East African market), 2013 (terrorist attacks).

> 19See https://en.wikipedia.org/wiki/United ~~S~~ tates for the United States. Accessed 03-15-2019.

> 20See https://www.bbc.com/news/world-us-canada-16761057 for the United States. Accessed 03-152019.