public function someplugin_select() {
            $options = get_option( 'plugin_252calc');
            echo $options; //shows the correct value selected
            $items = array();
            for ($i=6; $i <=10; $i+= 0.1)
            {
                $items[] = $i;
            }

            echo '<select id="cf-nb" name="cf-nb">';
            foreach ( $items as $item )
            {
                echo '<option value="'. $item .'"';
                if ( $item == $options ) echo' selected="selected"';
                echo '>'. $item .'</option>';
            }

            echo '</select>';

        }