Whether you're nearing retirement or already there, you want low-volatility investments that generate income during your golden years. Investing in dividend stocks is a smart way to accomplish both goals.

Companies that have a consistent track record of paying dividends year after year tend to be stable, and dividends are a great source of passive income. Here are three dividend stocks that could make your retirement richer.

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1. Physicians Realty Trust

Physicians Realty Trust (DOC) is a real estate investment trust with a $5 billion portfolio, 94% of which is held in medical office buildings. Medical office REITs, or real estate investment trusts, tend to be relatively recession-resistant because people still need healthcare in a struggling economy. REITs in general are a good source of dividend income because SEC regulations require them to pay out at least 90% of their taxable income as dividends.

With a dividend yield of 5.3%, Physicians Realty Trust should be appealing to income investors. Its $5 billion portfolio accounts for just a tiny sliver of the medical office real estate market, giving it plenty of room to grow, particularly as healthcare shifts away from hospital campuses and more toward outpatient care. As Fool contributor Matthew Frankel wrote in September 2020, the company sees big opportunities in acquiring the nearly 70% of the medical office market that's owned by healthcare providers and hospitals. 

But the stability of its existing portfolio also makes Physicians Realty Trust an attractive investment. Its portfolio is 60% leased to investment-grade tenants, and 89% of its tenants are affiliated with a major health system. Despite pandemic challenges, management reported that 99.6% of fourth quarter rents were collected as due during a Feb. 25 earnings call

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2. Costco

Costco's (COST 1.32%) reliability has the hallmarks of a strong retirement stock. It primarily sells consumer staples that people need. The bulk of its profits come from membership fees that start at $60 annually, and members renew at a rate of about 90%.

But its dividend yield is just 0.8%, which looks pretty measly when you consider that the S&P 500 index's current yield is about 1.5%. Still, income investors shouldn't dismiss the warehouse giant. Costco's share prices have shot up about 350% in the past decade, while the S&P 500 rose by 190%.

When share prices surge, it pushes down the yield, even when the company is consistently increasing its annual dividend payment -- as Costco has done for the past 16 consecutive years. In the past five years, the retailer has grown its annual dividend at an average annual rate of 12.6%. Plus, on four occasions since 2012, Costco has surprised investors with a special dividend, the most recent of which was an eye-popping $10 a share in December. While a special dividend is no substitute for reliable income, it's certainly a nice bonus on top of its growing quarterly payments.

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3. Johnson & Johnson

There's no such thing as a guaranteed dividend, but Johnson & Johnson (JNJ -2.28%) is about as close as you can get. The healthcare behemoth is a member of the elite Dividend Kings, with 58 years of consecutive dividend increases to its name and a current yield of 2.54%. Its most recent increase amounted to 6.3%.

Putting aside whether its single-dose COVID-19 vaccine will or won't have a long-term impact on Johnson & Johnson's share prices, the big reason to have this stock in your retirement portfolio is because this healthcare titan's stability is practically impossible to rival. It's an incredibly well-diversified business, with pharmaceutical and medical devices accounting for 80% of its sales, while consumer products drive the remaining 20%. Just slightly over half of its revenue is generated within the U.S. It's also one of just two companies (the other being Microsoft) that has a higher credit rating than the U.S. government

With free cash flow of $20 billion in fiscal 2020, of which $10.5 billion was paid out in dividends, Johnson & Johnson can easily sustain its dividend. Investors looking for high growth may be disappointed, but it's an ideal stock for those looking for low volatility and investment income that can outpace inflation for the foreseeable future.