This is completely normal, and is part of the Google’s Personalised Search. Google are continuously looking at new techniques to deliver the best user experience for each individual whilst using their search engine. So, in late 2004, Google introduced this feature to their product. Ultimately, Personalised Search is a product that looks to serve you the results that they believe are more attractive to you as an individual user (based on historical data, and previous website visits).
To gain the results that are shown to the majority of users, you will need to disable personalised search. Depending on the browser you are using will depend on how you can disable this feature. For example, in Google Chrome, you can also search Google by using the Incognito search function.