Average job tenure is growing shorter and shorter but that doesn’t mean hiring managers don’t get worried when they see someone that can’t hold a job down without changing every year or two. It’s a big investment of time and money to hire someone new and they want to make sure that you are not fickle or immature about your choices. If you can provide context about inevitable job changes that weren’t your fault (e.g. you had to move across the country to be with your spouse, the company closed down), that will put the interviewer at ease.