fix off-by-one year formatting error

src/app/core/models/termcode.ts

@@ -7,7 +7,7 @@ export class YearCode {
 
   public get fromYear(): number {
     const century = 1900 + parseInt(this.centuryOffset, 10) * 100;
-    const year = century + parseInt(this.yearOffset, 10);
+    const year = century + parseInt(this.yearOffset, 10) - 1;
     return year;
   }