Use the data in the table to construct a bar graph of investment in physical capital during the early 2000s. Explain how changes in the level of investment in physical capital are likely to affect productivity in our economy.

Year Investment in Physical Capital (in billions of 2000 dollars) 1999 $1,559 2000 $1,679 2001 $1,646 2002 $1,568 2003 $1,667 Source: Statistical Abstract of the United States, 2006, p. 523.