XF 2.2 How to have and display a cumulative total of a variable sent to the member_list_macros template?

[Stuart Wright]

I have this code in the custom whoreplied_list template

                    <li class="block-row block-row--separated userList-row js-filterSearchable">
                        <xf:set var="$extraTemplate">
                            <div class="whoreplied--postcount">
                                <xf:if is="$canSearch">
                                    <a href="{{ link('search/search', '', {'c[users]':{$user.username}, 'search_type':'post', 'c[thread]': $thread.thread_id, 'order':'date'}) }}" target="_blank" title="{{ phrase('whoreplied_see_posts')|for_attr }}">
                                        {$user.ThreadUserPost.{$thread.thread_id}.post_count|number}
                                    </a>
                                <xf:else />
                                    {$user.ThreadUserPost.{$thread.thread_id}.post_count|number}
                                </xf:if>
                                ({{ (100* $user.ThreadUserPost.{$thread.thread_id}.post_count / ($thread.reply_count))|number(2) }}%)
                            </div>
                        </xf:set>
                        <xf:macro template="member_list_macros"
                                  name="item"
                                  arg-user="{$user}"
                                  arg-extraData="{$extraTemplate}"
                                  arg-extraDataBig="1"
                                  />
                    </li>

which has this line added

({{ (100* $user.ThreadUserPost.{$thread.thread_id}.post_count / ($thread.reply_count))|number(2) }}%)

which is a tweak to @Xon's

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Who Replied

Apr 6, 2018

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• Xon
• forums reply
• Add-ons [2.x]

addon and the tweak displays the % total of posts in the thread for each person.

What I'd like to do is add the cumulative percentage so I can see how many people are responsible for 50% of the posts in a thread.
Is there a way to have an additional number for the cumulative value of

{{ (100* $user.ThreadUserPost.{$thread.thread_id}.post_count / ($thread.reply_count))|number(2) }}

?
I'm thinking a variable which has the value added to it in each operation of the macro.
Thanks