As altitude increases, the available amount of oxygen to sustain mental and physical alertness decreases with the overall air pressure, though the relative percentage of oxygen in air, at about 21%, remains practically unchanged up to 21,000 metres (70,000 ft).
  State legislators in Texas (both representatives and senators) make a salary of $7,200 per year.
Customer service lines and call centers have become increasingly common as the information age firmly sets in. The average salary for customer service and call center representatives is $29,000. Individual numbers may range between $23,400 and $35,200 for the most part. Managerial positions often earn larger salaries. The average hourly wage for representatives is between $10 and $15, with a 50% boost for overtime. Annual bonuses can amount to as much as $2,000. Some call center reps earn extra money through profit sharing and commissions from selling products, amounting to an extra $1,000 to $10,000 per year.