public function AllYears()
	{
		$result = array_reduce( $this->contexts, function( $carry, $context ) {

			if ( ! isset( $context['period'] ) ) return $carry;
			// Get the year of the start date
			$parts = explode( "-", $context['period']['startDate'] );
			$carry[ $parts[0] ] = isset( $carry[ $parts[0] ] ) ? $carry[ $parts[0] ] + 1 : 1;
			$parts = explode( "-", $context['period']['endDate'] );
			$carry[ $parts[0] ] = isset( $carry[ $parts[0] ] ) ? $carry[ $parts[0] ] + 1 : 1;
			return $carry;

		}, array() );

		ksort( $result );
		return array_keys( $result );
	}