Over the last couple of centuries there has been a steady increase in wages for both unskilled workers...
....and production workers. A lot of this growth is a result of the increases in worker productivity due the industrial revolution of the late 1770s and 1800s. However, over the last 40 years, this long-term growth has stopped or slowed down...
Updated 3/25/13: This Production Workers series includes benefits all the way back to when benefits became measurable in the early 1900s. More detailed definition can be found here.
...even though the GDP per person continues to grow. At the same time, the growth rate of GDP per worker has slowed compared to the overall growth of the economy.
Looking at just goods-producing industries, wages dropped for manufacturing, construction, and mining & logging since their a peak in the 1970s.
But among so-called service industries over the same time period there has been either a dip in wages or no real growth. Exceptions include jobs in the financial industry, education & health services and "other" services (which is mashup of occupations like auto mechanics, pet care, promoting political causes or religious activities).
Data Sources for Wages (See bibliography for more references)
Officer, Lawrence H., and Samuel H. Williamson. “Annual Wages in the United States, 1774–Present.” MeasuringWorth.com, 2011. http://www.measuringworth.com/uswage/.
US Bureau of Labor Statistics. “Table B-8. Average hourly and weekly earnings of production and nonsupervisory employees on private nonfarm payrolls by industry sector, seasonally adjusted.” November 2012. http://www.bls.gov/webapps/legacy/cesbtab8.htm.
Designer's Notes: Some of my thoughts on the design and the approaches I used.