1994 1997 2003 Lowest $9,594 or less $22,400 or less $34,000 or less Lower middle $9,595–$17,992 $22,401–$29,992 $34,001–$48,000 Upper middle $17,993–$25,771 $29,993–$40,888 $48,001–$66,900 Highest Greater than $25,771 Greater than $40,888 Greater than $66,900