It's really difficult to pin a number on how many "employees" were under Escobar's control due to the nature of the Mendellin (Escobar's organization) and Cali cartels. Although these cartels are what are generally described as "vertical organizations," meaning that the manufacture, and distribution of drugs were all under the control of the cartels themselves, much of the violence within Colombia were contracted out, often to young men in the shantytowns of Colombian cities known as sicarios.

Before Escobar and the major cartels began to be a huge player in Colombian politics, the country had been in a long period of political violence and instability known as la Violencia (if you have read One Hundred Years of Solitude, the political wars in the novel refer to this period). The generally accepted beginning of la Violencia in 1948, when the Liberal leader Jorge Eliecer Gaitan was assassinated amidst the in-power Conservative Party's fear that they might lose the presidency in the next election due to the economic issues that were occurring under their time in power.

After the 1948 assassination, violence in Colombia increased dramatically, and the Liberal Party employed the help of local guerrilla groups and rogue "bandits," often based in the major cities, to help them fight the Conservative military. Although the Liberal Party had used guerrilla groups previously during their rise to power in the 1930s, the guerrilla groups during la Violencia were larger, more structured, and more violent. In 1948 alone, Colombia saw 43,557 deaths.

Not only did the two major political groups engage in extreme violence against one another, but local politicians often hired peasants and poor city-dwellers to carry out violent deeds against political opponents and individuals that they had grudges against. Furthermore, many peasants rose against their hacienda owners, and hacienda owners often incited violence amongst their peasants in order to divert any violence that could end their own economic stature. With the combination of both national and local political violence, Colombia was in shambles, and the death toll from 1948-1953 reached approximately 144,370 bodies.

In 1953, Army Commander Gustavo Rojas Pinilla lead a military coup against the current conservative president and granted amnesty to the Liberal guerrilla fighters; however, not all of the fighters accepted this amnesty and some fighting between the government and radicalized guerrilla and bandit groups continued into the mid-1950s. By 1957 the majority of political violence had disappeared under the establishment of the bipartisan National Front group, which would alternate between Conservative and Liberal control as an attempt to quell partisan violence and cut off political and economic resources to any guerrilla groups still associated with the Liberal Party. Not all guerrilla groups were eradicated, however, and many communist groups joined together to form the fuerzas armadas revolucionarias de Colombia (FARC) in the 1960s.

So, by the rise of the cartels in the mid-1970s, Colombian violence was often associated with rogue guerrilla and bandit groups that were loosely-affiliated with the major party that they were working for. Thus, it made sense for the cartels to often outsource their violence to individuals that were not officially part of the cartel, and the use of sicarios became especially prominent after 1984, when Pablo Escobar hired two young motorcyclists from the slums of Mendellin to assassinate the Colombian Secretary of Justice, Rodrigo Lara Bonilla, who, at the time, was working with the United States government to extradite Escobar. It is after the assassination of Lara Bonilla that much of the random and chaotic violence associated with the Cartels occurred, as the sicarios offered their services to anyone who could pay their price, whether that be narcotraficantes looking to eliminate a political enemy or a hurt lover looking to eliminate their cheating partner.

Sicarios definitely weren't the only individuals involved in cartel violence, as there were many individuals that actually had proper affiliations with the organizations, but a lot of the violence in Colombia during the 1980s can be traced back to these hitmen.