Number of comments appearing before font awesome icon.

I am trying the following code to show number of comments for a post but instead of being shown after the icon, it is being displayed before it.

Firebug shows comments number outside the span tag.

echo '<span class="comments-link"><i class="fa fa-comment"></i>' . comments_number( __('Leave a comment', 'blankslate'), __('1 Comment','blankslate'), __('% Comments','blankslate')) .'</span>';