diff --git a/models/countries.model.ts b/models/countries.model.ts
index c1c88a0..9490ecf 100644
--- a/models/countries.model.ts
+++ b/models/countries.model.ts
@@ -58,7 +58,7 @@ export interface ICountry {
     },
     dialling: {
         calling_code: string[],
-        national_prefix: string,
+        national_prefix: string | null,
         national_number_lengths: number[],
         national_destination_code_lengths: number[],
         international_prefix: string | number
@@ -79,9 +79,9 @@ export interface ICountry {
         fao: number,
         imf: number,
         ar5: string | number,
-        address_format: string,
-        eu_member: boolean,
-        vat_rates: {
+        address_format: string | null,
+        eu_member: boolean | null,
+        vat_rates: null | {
             standard: number,
             reduced: number[],
             super_reduced: number,
@@ -99,4 +99,4 @@ export interface ICountry {
 
 export class Countries {
     [key: string]: ICountry;
-}
\ No newline at end of file
+}