Women in the U.S. make up nearly half of the entry-level workforce, but comprise only a fifth of the C-suite. Yet any assumption that this scarcity at the top is due to a lack of ambition is wrong, according to CNBC and SurveyMonkey's new Women at Work survey. 

Among the 1,068 working U.S. women who participated in the survey, 54% said they are "very ambitious" when it comes to their career and 35% said they are "somewhat ambitious." Meanwhile, just 3% said they're "not ambitious at all."