during which stage are your earnings likely at their lowest level?

Earnings are likely at their lowest level during the "Education and training" stage. This is the period when individuals are generally not earning a full salary as they invest time in acquiring necessary skills, education, and qualifications before entering the workforce fully. As one progresses beyond this stage into early career, mid-career, and late career stages, earnings tend to increase due to gaining experience, advancing skills, and taking on more responsibilities.