The seeds of the Little War were planted in a restless summer during the mid-1960s, with sit-ins and student demonstrations as youth tested its strength. By the early 1970s over 75 percent of the people living on Earth were under 21 years of age. The population continued to climb—and with it the youth percentage.In the 1980s the figure was 79.7 percent.In the 1990s, 82.4 percent.In the year 2000—critical mass.