During the 1990s after NAFTA was signed, industrial development grew rapidly with foreign investment. Large factories known as maquiladoras were built to export manufactured goods to the United States and Canada. Today, most of the maquiladoras produce electronics, automobile, and aerospace components. There are more than 406 companies operating under the federal IMMEX or Prosec program in Chihuahua. The large portion of the manufacturing sector of the state is 425 factories divided into 25 industrial parks accounting for 12.47% of the maquiladoras in Mexico, which employ 294,026 people in the state. While export-driven manufacturing is one of the most important components of the state's economy, the industrial sector is quite diverse and can be broken down into several sectors, which are: electronics, agro-industrial, wood base manufacturing, mineral, and biotech. Similar to the rest of the country, small businesses continue to be the foundation of the state’s economy. Small business employs the largest portion of the population.[citation needed]

What agreement sparked industrial development during the 1990s?