Such impressive health outcomes did not occur in isolation from its socio-economic development context. From 1969 to 2009, its gross national income (GNI) grew from US$210 to $3,760 in current figures, or 17 times over 40 years. During the 1970s and 1980s, Thailand invested heavily in highways that connect the isolated and impoverished Northeast and North to Bangkok; electrification throughout the country; as well as expansion of school enrollment for both boys and girls. As a result, the positive spillover effects also benefited the public health sector. As economic growth accelerated in the mid-1980s and 1990s, the country continued to finance infrastructure projects which brought greater connectivity, wider access to electricity and safe drinking water and clean sanitation, primary and secondary schools, and primary health centres in rural areas across the country.