Try something like this on your line 3 to group into buckets:
| eval "Total Clicks"=case(ArticleCount>=1 AND ArticleCount<=50,"1-50", ArticleCount>50 AND <=100,"51-100", ArticleCount>100 AND ArticleCount<=150,"101-150", ArticleCount>150 AND ArticleCount<=200,"151-200", ArticleCount>201,">201")
That should give you the buckets your looking for. Then, to get the percentage for each bucket, try this:
| eventstats sum(ArticleCount) as Percent | eval "Percent Views"=round(ArticleCount*100/Percent,1)
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