How to add blank line between comments

Newbie here. The comments page is pretty crowded so I thought adding a blank line in between comments would make it cleaner and clearer. Here’s the top part of the comments.php. What/where can I add a blank line? Thanks in advance.
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<?php if ( !empty($post->post_password) && $_COOKIE[‘wp-postpass_’ . COOKIEHASH] != $post->post_password) : ?>
<p><?php _e(‘Enter your password to view comments.’); ?></p>
<?php return; endif; ?>

<h2 id=”comments”><?php comments_number(__(‘No Comments’), __(‘1 Comment’), __(‘% Comments’)); ?>
<?php if ( comments_open() ) : ?>
“>»
<?php endif; ?>
</h2>

<?php if ( $comments ) : ?>
<ul id=”commentlist”>

<?php $i=1; ?>
<?php foreach ($comments as $comment) : ?>
<li id=”comment-<?php comment_ID() ?>”>
<div class=”numberbox”><?php echo $i; ?></div>
<div class=”commentbox”>
<?php comment_text() ?>
<p><cite><?php comment_type(__(‘Comment’), __(‘Trackback’), __(‘Pingback’)); ?> <?php _e(‘by’); ?> <?php comment_author_link() ?> — <?php comment_date() ?> @ “><?php comment_time() ?></cite> <?php edit_comment_link(__(“Edit This”), ‘ |’); ?></p>
</div>