The number of new cars sold in the United States over a 20-year period can vary significantly depending on economic conditions, consumer preferences, and various other factors. I can provide you with historical data for new car sales in the United States up until my knowledge cutoff date in September 2021. However, please note that these figures are subject to change, and I recommend consulting more recent sources for up-to-date information.

Here's a rough overview of new car sales in the United States over a 20-year period, from 2001 to 2020:

  1. 2001: Approximately 17.2 million new cars were sold.
  2. 2002: Approximately 16.8 million new cars were sold.
  3. 2003: Approximately 16.7 million new cars were sold.
  4. 2004: Approximately 16.9 million new cars were sold.
  5. 2005: Approximately 17 million new cars were sold.
  6. 2006: Approximately 16.5 million new cars were sold.
  7. 2007: Approximately 16.1 million new cars were sold.
  8. 2008: Approximately 13.2 million new cars were sold (a notable decrease due to the global financial crisis).
  9. 2009: Approximately 10.4 million new cars were sold (another decrease during the financial crisis).
  10. 2010: Approximately 11.6 million new cars were sold.
  11. 2011: Approximately 12.8 million new cars were sold.
  12. 2012: Approximately 14.5 million new cars were sold.
  13. 2013: Approximately 15.6 million new cars were sold.
  14. 2014: Approximately 16.5 million new cars were sold.
  15. 2015: Approximately 17.5 million new cars were sold.
  16. 2016: Approximately 17.6 million new cars were sold.
  17. 2017: Approximately 17.2 million new cars were sold.
  18. 2018: Approximately 17.3 million new cars were sold.
  19. 2019: Approximately 17 million new cars were sold.
  20. 2020: Approximately 14.5 million new cars were sold (a decrease due to the COVID-19 pandemic).

Please note that these figures are approximate and represent the total number of new cars sold in the United States for each respective year. The annual sales figures can fluctuate due to various economic and market factors. For the most current and accurate data, it's recommended to consult the latest reports and statistics from relevant sources like the U.S. Bureau of Economic Analysis or industry associations.