second largest export earner, after coffee. Economic growth continued in the 1960s, largely as a result of industrialization. Under the stimulus of the newly formed Central American Common Market, Nicaragua achieved a certain degree of specialization in processed foods, chemicals, and metal manufacturing. By the end of the 1960s, however, import substitution industrialization as a stimulus for economic growth had been exhausted. The 1969 Football War between Honduras and El Salvador, two members of the CACM, effectively suspended attempts at regional integration until 1987, when the Esquipulas II agreement was signed. By 1970 the industrial sector was undergoing little additional import substitution, and the collapse of the CACM meant that Nicaragua's economic growth, which had come from the expanding manufacturing sector, halted. Furthermore, the manufacturing firms that had developed under the tariff protection of the CACM were generally high-cost and inefficient; consequently, they were at a disadvantage when exporting outside the region. Although statistics for the period 1970–77 seemed to show continued economic growth, they reflected fluctuations in demand rather than a continued diversification of the economy. The gross domestic product rose 13% in 1974, the biggest boom in Nicaragua's economic history. However, these figures largely represented the jump in construction as the country struggled to rebuild after the disastrous 1972 earthquake. Likewise, the positive growth in 1976–77 was merely a reflection of the high world prices for coffee and cotton. Positive GDP growth rates in the 1970s masked growing structural problems in the economy. The 1972 earthquake destroyed much of Nicaragua's industrial infrastructure, which had been located in Managua. An estimated 10,000 people were killed and 30,000 injured, most of them in the capital area. The earthquake destroyed most government offices, the financial district of Managua, and about 2,500 small shops engaged in manufacturing and commercial activities. About 90% of city housing in Managua was left unstable. Government budget deficits and inflation were the legacies of the earthquake. The government increased expenses to finance rebuilding, which primarily benefited the construction industry, in which the Somoza family had strong financial interests. Because earthquake reconstruction generated few new revenues, except through borrowing, most of the resulting public deficits were covered by foreign loans. In the late 1970s, Nicaragua had the highest level of foreign indebtedness in Central America. Most of the benefits of the three decades of growth after World War II were concentrated in a few hands. Several groups of