Beta-plus (Î² +) radiation is the emission of positrons, which are the antimatter form of electrons. When a positron slows to speeds similar to those of electrons in the material, the positron will annihilate an electron, releasing two gamma photons of 511 keV in the process.
The Congressional Budget Office puts the cut-off lower, at $347,000 in 2007, or $252,000 after subtracting federal taxes and adding back transfers. Measured by net worth, rather than income, the top 1% started at $6.9m in 2009, according to the Federal Reserve, down 23% from 2007.
National Averages. According to the U.S. Census Bureau, the average salary for all Americans was $51,017 in 2012, down very slightly from 2011's mean of $51,100. That is still 8.7 percent below the average salary in 2007.Women made 77 percent of what men make on average across the country in 2012.hite workers earned an annual average of $57,000 in 2012; African-Americans, $33,300; Asian-Americans, $68,600; and Hispanics, $39,000. For the third year in a row, the percentage of Americans living at or below the poverty level -- those individuals earning $11,720 or less -- has remained at a high of 15 percent.