Google has a complex and very advanced mechanism of measuring the relevancy of your website to specific keyword searches. Google keeps a detailed database of all web pages it visits and for its search results, it selects the most relevant in content websites and ranks them by their importance.
Google assigns ranks to web pages it visits to measure their importance. The rank is a quantitative way of assessing the quality and importance of your web page. The higher the rank is, the more important your web site is perceived by Google and higher it will come out it in relevant search results. Thus, a web page with a rank 6 will come up higher in search results than a web page with a rank 4, assuming their relevancy is the same. The longer your website is alive, the higher its rank will become.