NationMaster Scroll down to the interactive map - mouse over each country to see its fertility rate. The necessary replacement rate is about 2.1. USA is on the brink. Many countries (Canada, Japan, Italy, Russia, for a few) are below this.
China's total fertility rate has decreased over time. In 1950-1955 the average fertility rate for a women was just above 6.0. Over the space of 50-55 years, the fertility rate has decreased. In 2010, the fertility rate fell to below 2.0.
The fertility rates in America have been declining dramatically. A lot of adults have been deciding not to be parents because they now have this freedom of choice. Many of these adults are choosing not to be parents because of severe economic problems. Knowing that you weren't economically stable, would you still have children or would you choose not to?