public function set_period( $period = 'today' ) {

		$now = current_time( 'timestamp' );

		switch ( $period ) {

			case 'all_time':
				$curr_start = 0;
				$curr_end   = $now;

				$prev_start = 0;
				$prev_end   = $now;
				break;

			case 'last_year':
				$curr_start = strtotime( 'first day of january last year', $now );
				$curr_end   = strtotime( 'last day of december last year', $now );

				$prev_start = strtotime( 'first day of january last year', $curr_start );
				$prev_end   = strtotime( 'last day of december last year', $curr_start );
				break;

			case 'year':
				$curr_start = strtotime( 'first day of january this year', $now );
				$curr_end   = strtotime( 'last day of december this year', $now );

				$prev_start = strtotime( 'first day of january last year', $now );
				$prev_end   = strtotime( 'last day of december last year', $now );
				break;

			case 'last_month':
				$curr_start = strtotime( 'first day of previous month', $now );
				$curr_end   = strtotime( 'last day of previous month', $now );

				$prev_start = strtotime( 'first day of previous month', $curr_start );
				$prev_end   = strtotime( 'last day of previous month', $curr_start );
				break;

			case 'month':
				$curr_start = strtotime( 'first day of this month', $now );
				$curr_end   = strtotime( 'last day of this month', $now );

				$prev_start = strtotime( 'first day of previous month', $now );
				$prev_end   = strtotime( 'last day of previous month', $now );
				break;

			case 'last_week':
				$curr_start = strtotime( 'monday this week', $now - WEEK_IN_SECONDS );
				$curr_end   = $now;

				$prev_start = strtotime( 'monday previous week', $curr_start - WEEK_IN_SECONDS );
				$prev_end   = $curr_start - DAY_IN_SECONDS;
				break;

			case 'week':
				$curr_start = strtotime( 'monday this week', $now );
				$curr_end   = $now;

				$prev_start = strtotime( 'monday previous week', $now );
				$prev_end   = $curr_start - DAY_IN_SECONDS;
				break;

			case 'yesterday':
				$curr_start = $now - DAY_IN_SECONDS;
				$curr_end   = $curr_start;

				$prev_start = $curr_start - DAY_IN_SECONDS;
				$prev_end   = $prev_start;
				break;

			case 'today':
			default:
				$curr_start = $now;
				$curr_end   = $now;

				$prev_start = $now - DAY_IN_SECONDS;
				$prev_end   = $prev_start;

		}// End switch().

		$this->dates = array(
			'current'  => array(
				'start' => strtotime( 'midnight', $curr_start ),
				'end'   => strtotime( 'tomorrow', $curr_end ) - 1,
			),
			'previous' => array(
				'start' => strtotime( 'midnight', $prev_start ),
				'end'   => strtotime( 'tomorrow', $prev_end ) - 1,
			),
		);

	}