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.
That year you needed $426,439 to be in the top 1%. The 1% as a group pay a bigger share of income taxes than their share of adjusted gross income: As a group, the top 1% earned nearly 19% of all adjusted gross income reported in 2011 and paid 35% of all federal income taxes. Of course, adjusted gross income doesn't measure all income, only what must be reported for taxes.