As of March 2002 here is a list of all country codes and associated country names returned by CountryHawk:

AC=Ascension Island
AD=Andorra
AE=United Arab Emirates
AF=Afghanistan
AG=Antigua and Barbuda
AI=Anguilla
AL=Albania
AM=Armenia
AN=Netherlands Antilles
AO=Angola
AQ=Antarctica
AR=Argentina
AS=American Samoa
AT=Austria
AU=Australia
AW=Aruba
AZ=Azerbaijan
BA=Bosnia and Herzegovina
BB=Barbados
BD=Bangladesh
BE=Belgium
BF=Burkina Faso
BG=Bulgaria
BH=Bahrain
BI=Burundi
BJ=Benin
BM=Bermuda
BN=Brunei Darussalam
BO=Bolivia
BR=Brazil
BS=Bahamas
BT=Bhutan
BV=Bouvet Island
BW=Botswana
BY=Belarus
BZ=Belize
CA=Canada
CC=Cocos (Keeling) Islands
CD=Democratic Republic of Congo
CF=Central African Republic
CG=Republic of Congo
CH=Switzerland
CI=Cote d'Ivoire
CK=Cook Islands
CL=Chile
CM=Cameroon
CN=China
CO=Colombia
CR=Costa Rica
CU=Cuba
CV=Cap Verde
CX=Christmas Island
CY=Cyprus
CZ=Czech Republic
DE=Germany
DJ=Djibouti
DK=Denmark
DM=Dominica
DO=Dominican Republic
DZ=Algeria
EC=Ecuador
EE=Estonia
EG=Egypt
EH=Western Sahara
ER=Eritrea
ES=Spain
ET=Ethiopia
FI=Finland
FJ=Fiji
FK=Falkland Islands (Malvina)
FM=Federal State of Micronesia
FO=Faroe Islands
FR=France
GA=Gabon
GD=Grenada
GE=Georgia
GF=French Guiana
GG=Guernsey
GH=Ghana
GI=Gibraltar
GL=Greenland
GM=Gambia
GN=Guinea
GP=Guadeloupe
GQ=Equatorial Guinea
GR=Greece
GS=South Georgia and South Sandwich Islands
GT=Guatemala
GU=Guam
GW=Guinea-Bissau
GY=Guyana
HK=Hong Kong
HM=Heard and McDonald Islands
HN=Honduras
HR=Croatia/Hrvatska
HT=Haiti
HU=Hungary
ID=Indonesia
IE=Ireland
IL=Israel
IM=Isle of Man
IN=India
IO=British Indian Ocean Territory
IQ=Iraq
IR=Iran
IS=Iceland
IT=Italy
JE=Jersey
JM=Jamaica
JO=Jordan
JP=Japan
KE=Kenya
KG=Kyrgyzstan
KH=Cambodia
KI=Kiribati
KM=Comoros
KN=Saint Kitts and Nevis
KP=Democratic People's Republic of Korea
KR=Republic of Korea
KW=Kuwait
KY=Cayman Islands
KZ=Kazakhstan
LA=Lao People's Democratic Republic
LB=Lebanon
LC=Saint Lucia
LI=Liechtenstein
LK=Sri Lanka
LR=Liberia
LS=Lesotho
LT=Lithuania
LU=Luxembourg
LV=Latvia
LY=Libyan Arab Jamahiriya
MA=Morocco
MC=Monaco
MD=Moldova, Republic of
MG=Madagascar
MH=Marshall Islands
MK=Macedonia, Former Yugoslav Republic
ML=Mali
MM=Myanmar
MN=Mongolia
MO=Macau
MP=Northern Mariana Islands
MQ=Martinique
MR=Mauritania
MS=Montserrat
MT=Malta
MU=Mauritius
MV=Maldives
MW=Malawi
MX=Mexico
MY=Malaysia
MZ=Mozambique
NA=Namibia
NC=New Caledonia
NE=Niger
NF=Norfolk Island
NG=Nigeria
NI=Nicaragua
NL=Netherlands
NO=Norway
NP=Nepal
NR=Nauru
NU=Niue
NZ=New Zealand
OM=Oman
PA=Panama
PE=Peru
PF=French Polynesia
PG=Papua New Guinea
PH=Philippines
PK=Pakistan
PL=Poland
PM=St. Pierre and Miquelon
PN=Pitcairn Island
PR=Puerto Rico
PS=Palestinian Territories
PT=Portugal
PW=Palau
PY=Paraguay
QA=Qatar
RE=Reunion Island
RO=Romania
RU=Russian Federation
RW=Rwanda
SA=Saudi Arabia
SB=Solomon Islands
SC=Seychelles
SD=Sudan
SE=Sweden
SG=Singapore
SH=St. Helena
SI=Slovenia
SJ=Svalbard and Jan Mayen Islands
SK=Slovak Republic
SL=Sierra Leone
SM=San Marino
SN=Senegal
SO=Somalia
SR=Suriname
ST=Sao Tome and Principe
SV=El Salvador
SY=Syrian Arab Republic
SZ=Swaziland
TC=Turks and Caicos Islands
TD=Chad
TF=French Southern Territories
TG=Togo
TH=Thailand
TJ=Tajikistan
TK=Tokelau
TM=Turkmenistan
TN=Tunisia
TO=Tonga
TP=East Timor
TR=Turkey
TT=Trinidad and Tobago
TV=Tuvalu
TW=Taiwan
TZ=Tanzania
UA=Ukraine
UG=Uganda
UK=United Kingdom
UM=US Minor Outlying Islands
US=United States
UY=Uruguay
UZ=Uzbekistan
VA=Holy See (City Vatican State)
VC=Saint Vincent and the Grenadines
VE=Venezuela
VG=Virgin Islands (British)
VI=Virgin Islands (USA)
VN=Vietnam
VU=Vanuatu
WF=Wallis and Futuna Islands
WS=Western Samoa
YE=Yemen
YT=Mayotte
YU=Yugoslavia
ZA=South Africa
ZM=Zambia
ZW=Zimbabwe
XX=Other
EU=European Union