@Target: Since I found for the area different numbers in different tables in Wikipedia, I took a list from the world factbook of the CIA and converted it in the format you requested:
["Afghanistan"]=652230,
["Aland Islands"]=1552,
["Albania"]=28748,
["Algeria"]=2381741,
["American Samoa"]=199,
["Andorra"]=468,
["Angola"]=1246700,
["Anguilla"]=91,
["Antarctica"]=14000000,
["Antigua and Barbuda"]=443,
["Argentina"]=2780400,
["Armenia"]=29743,
["Aruba"]=180,
["Australia"]=7741220,
["Austria"]=83871,
["Azerbaijan"]=86600,
["Bahamas"]=13880,
["Bahrain"]=760,
["Bangladesh"]=143998,
["Barbados"]=430,
["Belarus"]=207600,
["Belgium"]=30528,
["Belize"]=22966,
["Benin"]=112622,
["Bermuda"]=54,
["Bhutan"]=38394,
["Bolivia"]=1098581,
["Bonaire"]=294,
["Bosnia and Herzegovina"]=51197,
["Botswana"]=581730,
["Bouvet Island"]=49,
["Brazil"]=8514877,
["British Indian Ocean Territories"]=54400,
["British Virgin Islands"]=151,
["Brunei"]=5765,
["Bulgaria"]=110879,
["Burkina Faso"]=274200,
["Burundi"]=27830,
["Cambodia"]=181035,
["Cameroon"]=475440,
["Canada"]=9984670,
["Cape Verde"]=4033,
["Cayman Islands"]=264,
["Central African Republic"]=622984,
["Chad"]=1284000,
["Chile"]=756102,
["China"]=9596960,
["Christmas Island"]=135,
["Colombia"]=1138910,
["Comoros"]=2235,
["Congo"]=342000,
["Cook Islands"]=236,
["Costa Rica"]=51100,
["Croatia"]=56594,
["Cuba"]=110860,
["Curacao"]=444,
["Cyprus"]=9251,
["Czech Republic"]=78867,
["Democratic Republic of the Congo"]=2344858,
["Denmark"]=43094,
["Djibouti"]=23200,
["Dominica"]=751,
["Dominican Republic"]=48670,
["East Timor"]=14874,
["Ecuador"]=283561,
["Egypt"]=1001450,
["El Salvador"]=21041,
["Equatorial Guinea"]=28051,
["Eritrea"]=117600,
["Estonia"]=45228,
["Ethiopia"]=1104300,
["Falkland Islands"]=12173,
["Faroe Islands"]=1393,
["Fiji"]=18274,
["Finland"]=338145,
["France"]=643801,
["French Guiana"]=86504,
["French Polynesia"]=4167,
["French Southern Territories"]=55,
["Gabon"]=267667,
["Gambia The"]=11295,
["Georgia"]=69700,
["Germany"]=357022,
["Ghana"]=238533,
["Gibraltar"]=7,
["Greece"]=131957,
["Greenland"]=2166086,
["Grenada"]=344,
["Guadeloupe"]=1630,
["Guam"]=544,
["Guatemala"]=108889,
["Guernsey"]=78,
["Guinea"]=245857,
["Guinea-Bissau"]=36125,
["Guyana"]=214969,
["Haiti"]=27750,
["Heard Island and McDonald Islands"]=412,
["Honduras"]=112090,
["Hong Kong"]=1108,
["Hungary"]=93028,
["Iceland"]=103000,
["India"]=3287263,
["Indonesia"]=1904569,
["Iran"]=1648195,
["Iraq"]=438317,
["Ireland"]=70273,
["Isle of Man"]=572,
["Israel"]=20770,
["Italy"]=301340,
["Ivory Coast"]=322463,
["Jamaica"]=10991,
["Japan"]=377915,
["Jersey"]=116,
["Jordan"]=89342,
["Kazakhstan"]=2724900,
["Kenya"]=580367,
["Kiribati"]=811,
["Kuwait"]=17818,
["Kyrgyzstan"]=199951,
["Laos"]=236800,
["Latvia"]=64589,
["Lebanon"]=10400,
["Lesotho"]=30355,
["Liberia"]=111369,
["Libya"]=1759540,
["Liechtenstein"]=160,
["Lithuania"]=65300,
["Luxembourg"]=2586,
["Macau"]=28,
["Macedonia"]=25713,
["Madagascar"]=587041,
["Malawi"]=118484,
["Malaysia"]=329847,
["Maldives"]=298,
["Mali"]=1240192,
["Malta"]=316,
["Marshall Islands"]=181,
["Martinique"]=1128,
["Mauritania"]=1030700,
["Mauritius"]=2040,
["Mayotte"]=374,
["Mexico"]=1964375,
["Micronesia"]=702,
["Moldova"]=33851,
["Monaco"]=2,
["Mongolia"]=1564116,
["Montenegro"]=13812,
["Montserrat"]=102,
["Morocco"]=446550,
["Mozambique"]=799380,
["Myanmar"]=676578,
["Namibia"]=824292,
["Nauru"]=21,
["Nepal"]=147181,
["Netherlands Antilles"]=999,
["Netherlands"]=41543,
["New Caledonia"]=18575,
["New Zealand"]=267710,
["Nicaragua"]=130370,
["Niger"]=1267000,
["Nigeria"]=923768,
["Niue"]=260,
["Norfolk Island"]=36,
["North Korea"]=120538,
["Northern Mariana Islands"]=464,
["Norway"]=323802,
["Oman"]=309500,
["Pakistan"]=796095,
["Palau"]=459,
["Palestine"]=5860,
["Panama"]=75420,
["Papua New Guinea"]=462840,
["Paraguay"]=406752,
["Peru"]=1285216,
["Philippines"]=300000,
["Pitcairn Islands"]=47,
["Poland"]=312685,
["Portugal"]=92090,
["Puerto Rico"]=13790,
["Qatar"]=11586,
["Reunion"]=2512,
["Romania"]=238391,
["Russia"]=17098242,
["Rwanda"]=26338,
["Saba"]=13,
["Saint Helena"]=308,
["Saint Kitts and Nevis"]=261,
["Saint Lucia"]=616,
["Samoa"]=2831,
["San Marino"]=61,
["Sao Tome and Principe"]=964,
["Saudi Arabia"]=2149690,
["Senegal"]=196722,
["Serbia"]=77474,
["Seychelles"]=455,
["Sierra Leone"]=71740,
["Singapore"]=697,
["Slovakia"]=49035,
["Slovenia"]=20273,
["Solomon Islands"]=28896,
["Somalia"]=637657,
["South Africa"]=1219090,
["South Georgia and Sandwich Islands"]=3903,
["South Korea"]=99720,
["South Sudan"]=644329,
["Spain"]=505370,
["Sri Lanka"]=65610,
["St Martin"]=54,
["St Pierre Miquelon"]=242,
["St Vincent Grenadines"]=389,
["Sudan"]=1861484,
["Suriname"]=163820,
["Svalbard and Jan Mayen"]=62045,
["Swaziland"]=17364,
["Sweden"]=450295,
["Switzerland"]=41277,
["Syria"]=185180,
["Taiwan"]=35980,
["Tajikistan"]=143100,
["Tanzania"]=947300,
["Thailand"]=513120,
["Togo"]=56785,
["Tonga"]=747,
["Trinidad and Tobago"]=5128,
["Tunisia"]=163610,
["Turkey"]=783562,
["Turkmenistan"]=488100,
["Turks and Caicos Islands"]=948,
["Tuvalu"]=26,
["Uganda"]=241038,
["Ukraine"]=603550,
["United Arab Emirates"]=83600,
["United Kingdom"]=243610,
["United States"]=9826675,
["Uruguay"]=176215,
["US Virgin Islands"]=1910,
["Uzbekistan"]=447400,
["Vanuatu"]=12189,
["Vatican City State"]=0.44,
["Venezuela"]=912050,
["Vietnam"]=331210,
["Wallis and Futuna Island"]=142,
["Western Sahara"]=266000,
["Yemen"]=527968,
["Zambia"]=752618,
["Zimbabwe"]=390757,
It would be interesting to see the cache density by area...
