public static function print_perc_of_tested_users_field()
        {
            $field_name = 'perc_of_tested_users';
            printf('<input type="range" id="%1$s" name="nelioab_settings[%1$s]" min="10" max="100" step="5" value="%2$s" %3$s /><br>', $field_name, NelioABSettings::get_percentage_of_tested_users(), self::get_pro_details());
            ?>
			<span <?php 
            echo self::get_pro_details('description');
            ?>
 id="value_<?php 
            echo $field_name;
            ?>
"></span>
			<script type="text/javascript">
				jQuery("#<?php 
            echo $field_name;
            ?>
").on("input change", function() {
					var str = "<?php 
            $str = __('<strong>{value}%</strong> of the users that access your site will participate in the running experiments.', 'nelioab');
            $str = str_replace('"', '\\"', $str);
            echo $str;
            ?>
";
					var value = jQuery(this).attr('value');
					str = str.replace( '{value}', value );
					jQuery("#value_<?php 
            echo $field_name;
            ?>
").html(str);
				});
				jQuery("#<?php 
            echo $field_name;
            ?>
").trigger("change");
			</script>
			<div class="the-descr" style="display:none;"><span <?php 
            echo self::get_pro_details('description');
            ?>
><?php 
            _e('When a user accesses your website she may participate in your running experiments. This setting defines how likely it is for a visitor to be part of your tests.', 'nelioab');
            ?>
</span></div>
			<?php 
        }