In an early, simple hay tedder described in 1852 and manufactured in Edinburgh by the company of Mr. Slight, the two wheels, via a spur wheel and a pinion, drive a set of light wheels, the rake wheels; on these two rake wheels are mounted eight rakes, which pick up and disperse the hay.
It should be noted, how-ever, that only about 1 out of every 10 STEM workers has a high school diploma or less. Those with gradu-ate degrees in a STEM job earned more than $40 per hour, nearly $4.50 more per hour on average than those with non-STEM jobs.
As of 2011, approximately 16,590 biomedical engineers worked in the United States, earning an average wage of $42.48 an hour and a mean yearly income of $88,360. The median earnings reported to the Bureau of Labor Statistics for 2011 were $40.71 an hour and $84,670 a year.