Zip Code defining City & State fields

I am using the following javascript to prepopulate "City" and "State" fields.

var ZipData = {
02860:{state: "RI", city:"PROVIDENCE"},
02901:{state: "RI", city:"PROVIDENCE"},
02940:{state: "RI", city:"PROVIDENCE"},
03101:{state: "NH", city:"MANCHESTER"},
03106:{state: "NH", city:"HOOKSET"},
03253:{state: "NH", city:"MEREDITH"},
04240:{state: "ME", city:"LEWISTON"},
18002:{state: "PA", city:"LEHIGH VALLEY"},
21152:{state: "MD", city:"SPARKS"},
21203:{state: "MD", city:"BALTIMORE"},
21921:{state: "MD", city:"ELKTON"},
22901:{state: "VA", city:"CHARLOTTESVILLE"},
23173:{state: "VA", city:"RICHMOND"},
23452:{state: "VA", city:"VIRGINIA BEACH"},
27253:{state: "NC", city:"GRAHAM"},
27889:{state: "NC", city:"WASHINGTON"},
28269:{state: "NC", city:"CHARLOTTE"},
29202:{state: "SC", city:"COLUMBIA"},
29606:{state: "SC", city:"GREENVILLE"},
30096:{state: "GA", city:"DULUTH"},
30317:{state: "GA", city:"ATLANTA"},
30319:{state: "GA", city:"BROOKHAVEN"},
30348:{state: "GA", city:"ATLANTA"},
31004:{state: "GA", city:"BOLINGBROKE"},
32901:{state: "FL", city:"MELBOURNE"},
33483:{state: "FL", city:"DELRAY BEACH"},
33631:{state: "FL", city:"TAMPA"},
33785:{state: "FL", city:"INDIAN ROCKS BEACH"},
33810:{state: "FL", city:"LAKELAND"},
34113:{state: "FL", city:"NAPLES"},
34429:{state: "FL", city:"CRYSTAL RIVER"},
34698:{state: "FL", city:"DUNEDIN"},
35022:{state: "AL", city:"BESSEMER"},
43065:{state: "OH", city:"POWELL"},
43123:{state: "OH", city:"GROVE CITY"},
43420:{state: "OH", city:"FREMONT"},
44012:{state: "OH", city:"AVON LAKE"},
44306:{state: "OH", city:"AKRON"},
44839:{state: "OH", city:"HURON"},
45177:{state: "OH", city:"WILMINGTON"},
46361:{state: "IN", city:"MICHIGAN CITY"},
46504:{state: "IN", city:"BOURBON"},
46537:{state: "IN", city:"LAPAZ"},
46565:{state: "IN", city:"MISHAWAKA"},
46619:{state: "IN", city:"SOUTH BEND"},
46923:{state: "IN", city:"DELPHI"},
47918:{state: "IN", city:"ATTICA"},
52001:{state: "IA", city:"DUBUQUE"},
53151:{state: "WI", city:"NEW BERLIN"},
53214:{state: "WI", city:"WEST ALLIS"},
54751:{state: "WI", city:"MENOMONIE"},
55439:{state: "MN", city:"MINNEAPOLIS"},
55440:{state: "MN", city:"MINNEAPOLIS"},
55987:{state: "MN", city:"WINONA"},
57718:{state: "SD", city:"BLACK HAWK "},
57719:{state: "SD", city:"BOX ELDER"},
60002:{state: "IL", city:"ANTIOCH"},
60010:{state: "IL", city:"BARRINGTON"},
60025:{state: "IL", city:"GLENVIEW"},
60107:{state: "IL", city:"STREAMWOOD"},
60302:{state: "IL", city:"OAK PARK"},
60402:{state: "IL", city:"BERWYN"},
60430:{state: "IL", city:"HOMEWOOD"},
60438:{state: "IL", city:"LANSING"},
60546:{state: "IL", city:"RIVERSIDE"},
60559:{state: "IL", city:"WESTMONT"},
60614:{state: "IL", city:"CHICAGO"},
60616:{state: "IL", city:"CHICAGO"},
60618:{state: "IL", city:"CHICAGO"},
61709:{state: "IL", city:"BLOOMINGTON"},
62525:{state: "IL", city:"DECATUR"},
63101:{state: "MO", city:"ST LOUIS"},
63132:{state: "MO", city:"ST LOUIS"},
74134:{state: "OK", city:"TULSA"},
78288:{state: "TX", city:"SAN ANTONIO"},
80002:{state: "CO", city:"ARVADA"},
90212:{state: "CA", city:"BEVERLY HILLS"},
92660:{state: "CA", city:"NEWPORT BEACH"},
93063:{state: "CA", city:"SIMI VALLEY"},
95899:{state: "CA", city:"SACRAMENTO"},
97219:{state: "OR", city:"PORTLAND"}};
function SetCityValue(cZip)
{
this.getField("City").value = ZipData[cZip].city;

this.getField("State").value = ZipData[cZip].state;;
}

The script works fine for only those zip codes beginning with 1-9.  Zip codes beginning with a 0 fail to prepopulate.