Final answer:
Since 1990, the United States has experienced at least three recessions: the 1990-1991 recession, the 2001 recession, and the 2008-2009 recession, also known as the Great Recession.
Step-by-step explanation:
The United States has experienced several recessions since 1990. Specifically, the data provided indicates two recessions that started in the early 1990s: one in 1990-1991 and another in 2001. If we look at the historical trend since World War II, recessions have occurred on average every six years and have lasted for about 11 months. This trend suggests that the United States has faced fewer recessions than one might expect given the historical average, as it has been over two decades since the start of the timeframe in question.
Additionally, the period of recovery after recessions since the 1990s has been characterized by longer durations compared to previous recessions. It is important to also consider the significant recession of 2008-2009 known as the Great Recession, which had a profound impact on the global economy. Hence, including the 2008-2009 recession, there have been at least three recessions in the United States since 1990.