Final answer:
The question seeks the percentage of the US labor force that performs sales work, but the provided reference material does not contain this specific statistic. It provides examples of labor distribution in other industries and discusses labor force participation rates.
Step-by-step explanation:
The question asks about the percentage of the total US labor force that performs sales work. Though the provided information does not include the precise figure answering this specific question, an understanding of labor force statistics such as the labor force participation rate may offer insight. The labor force participation rate is a measure of the active portion of an economy's population that includes both the employed and those unemployed but looking for a job.
For the specific question regarding the percentage of the US labor force in sales, the closest related content is the example of labor force distribution in production, such as making shoes or refrigerators, which demonstrates how workers are allocated in various industries. However, without the exact data related to sales occupations, one can only infer that sales positions do make up a significant part of the labor force based on common knowledge and understanding of the economic structures.