| Year | Percent of total |
|---|---|
|
1993 |
37.9 |
|
1994 |
37.9 |
|
1995 |
37.4 |
|
1996 |
36.7 |
|
1997 |
36.3 |
|
1998 |
35.8 |
|
1999 |
34.8 |
|
2000 |
34.7 |
|
2001 |
34.6 |
|
2002 |
34.6 |
|
2003 |
34.7 |
|
2004 |
34.8 |
|
2005 |
34.2 |
|
2006 |
34.6 |
|
2007 |
34.2 |
|
2008 |
34.3 |
|
2009 |
34.3 |
|
2010 |
33.9 |
|
2011 |
34.3 |
|
2012 |
35.1 |
|
2013 |
34.9 |
|
2014 |
34.4 |
|
2015 |
33.8 |
|
2016 |
33.0 |
|
2017 |
33.4 |
|
2018 |
33.2 |
|
2019 |
33.2 |
|
2020 |
33.8 |
|
Source: U.S. Bureau of Labor Statistics. |
|