Default Attributes in Shortcode Not Working

I'm learning about shortcodes. My shortcode is working fine. But, I'm not getting the default values for the attributes.

function csf_cap_databaseinfo($atts,$content=null) {
    global $wpdb;

    shortcode_atts( array('title'=>'My Default', 'year'=>'1900'), $atts); 

    $greeting = $wpdb->get_results($wpdb->prepare("SELECT * FROM wp_test;")); 

     $out = '<h3>'.$atts['title'].'</h3> <h3>'.$atts['year'].'</h3><table>
                    <tr>
                        <th style="border:1px solid #e7e7e7; padding:10px; text-align:center">ID</th>
                        <th style="border:1px solid #e7e7e7; padding:10px; text-align:center">Greeting</th>
                    </tr>'; 

    foreach ($greeting as $greet)
        { 
        $out .= '<tr><td style="border:1px solid #e7e7e7; padding:10px; text-align:center">'. $greet->id .'</td>'; 
        $out .= '<td style="border:1px solid #e7e7e7; padding:10px; text-align:center">'. $greet->greeting .'</td></tr>';
        }

      $out .= '</table>'; 



        return $out; 

}

So, if someone types in [db-info] in a post, without any attributes, they aren't getting "My Default" and "1900". If they type in: [db-info title="Hello" year="1973"], it works as expected. What am I doing wrong?

Thanks.

-Laxmidi