WordPress shortcode to show the copyright year as well as years in business from given starting date.

wordpress_the_years.php

/**
 * Shortcode for the yearly display items
 *
 * @param [array] $atts The attributes passed to the shortcode
 *
 * @return void
 */
function showTheYear( $atts ){
    $yearStarted = if(isset($atts['yearStarted'])) intval($atts['yearStarted']) : 1999;
    $yearsInBusiness = if(isset($atts['years']))? true : false;
    $copyYear = if(isset($atts['copy']))? true : false;
    $copyText = if(isset($atts['copyText']))? $atts['copyText'] : '© This is our site';

    if ($yearsInBusiness)
        echo date("Y") - $yearStarted;
    elseif ($copyYear)
        echo $copyright_year = 'Copyright ' . date("Y") . $copyText;
}
add_shortcode('years', 'showTheYear');