swap default number with first item in collection

src/Collection/LocaleNumberFormatter.php

@@ -38,13 +38,6 @@ class LocaleNumberFormatter implements Formatter
      */
     public int $fraction_digits = 2;
 
-    /**
-     * Default number if $number_key isn't passed.
-     *
-     * @var float
-     */
-    public float $default_number = 0;
-
     /**
      * Format the date and time.
      *
@@ -65,7 +58,7 @@ public function format(Collection $items): string
         );
 
         return $formatter->format(
-            (float) $items->get($this->number_key) ?? $this->default_number
+            (float) $items->get($this->number_key) ?? $items->first()
         );
     }
 }