<P> Upon a sustained and distinguished track record of scholarly achievement within one's university and academic discipline, an associate professor may be promoted to professor (sometimes referred to as "full professor"). In most traditional colleges and universities, this position is always tenured; however, this may not be the case in a for - profit private institution or certain church - affiliated universities and colleges . </P> <P> The rank of professor is the highest of the standard academic ranks in the United States, and is held by 29.5% of U.S. academics . Advancement past the rank of professor typically involves administrative duties (e.g., department chair, dean, or provost) or selection for an honorary title or endowed chair . </P> <P> The absence of a mandatory retirement age contributes to "graying" of this occupation . The median age of American full professors (in 2006) was around 55 years . Very few people attain this position before the age of 40 . The annual salary of full professors averages at $99,000, although less so at non-doctoral institutions, and more so at private doctoral institutions (not including side income from grants and consulting, which can be substantial in some fields); in addition, institutions in major cities or high cost of living areas will pay higher salaries . Full professors earn on average about 70% more than assistant professors in the same institution . </P> <P> In addition to increasing salary, each promotional step also tends to come with increased administrative responsibilities . In some cases, these changes are offset by reduced teaching or research expectations . </P>

What is the retirement age for professors in usa
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