Extract the answer to the question from the following context. Question: In 20th century Brazil, the ages of 14, and briefly 12, were considered the what? Context: In Brazil, the minimum working age has been identified as fourteen due to continuous constitutional amendments that occurred in 1934, 1937, and 1946. Yet due to a change in the dictatorship by the military in the 80's, the minimum age restriction was reduced to the age of twelve but was reviewed due to reports of dangerous and hazardous working conditions in 1988. This led to the minimum age being raised once again to 14. Another set of restrictions was passed in 1998 that restricted the kinds of work youth could partake in, such as work that was considered hazardous like running construction equipment, or certain kinds of factory work. Although many steps were taken to reduce the risk and occurrence of child labour, there is still a high number of children and adolescents working under the age of fourteen in Brazil. It was not until recently in the 80's that it was discovered that almost nine million children in Brazil were working illegally and not partaking in traditional childhood activities that help to develop important life experiences.
The answer to this question is:
minimum working age