Who knows these things ... I'm not sure how can anyone claim that there has to be 70% of deep links, as if anyone has access to google inner workings. Its a matter of luck in my xp, if you manage to score a fitting link for the home page, it can make a huge difference, as will a number of deep links.
DEFINITION - A deep link is a hypertext link to a page on a Web site other than its home page. The "deep" refers to the depth of the page in a site's hierarchical structure of pages. Any page below the top page in the hierarchy (the home page) can thus be considered deep
Since you have a number of articles, you can see from the statistics which articles command better SERP. In that case, focus on those articles first. Get them to the top of the search result page. Once the visitors reach your website, you can direct them to read other articles.