Dividend stocks are the foundation of great retirement portfolios, because as history has shown, they far outperform non-dividend-paying stocks over the long term. However, not all dividend stocks are created equal, so this is where you must do your homework.

Fortunately for those of you who are reading this article, I’ve done the necessary homework and compiled a list of four great dividend stocks with high and safe yields of 4-9%, so let’s take a quick look at each to determine which one belongs in your portfolio.

1. Great-West Lifeco Inc.

Great-West Lifeco Inc. (TSX:GWO) is an international financial services holding company with interests in the insurance, retirement and investment services, and asset management businesses. It has operations in Canada, the United States, and Europe through its many subsidiaries, including Great-West Life, Canada Life, London Life, Irish Life, and Putnam Investments.

It pays a quarterly dividend of $0.346 per share, or $1.384 per share annually, which gives its stock a yield of about 4.2% at current levels. It’s also very important to note that the company’s 6.1% dividend hike in February has it on pace for 2016 to mark the second consecutive year in which it has raised its annual dividend payment.

2. Chorus Aviation Inc.

Chorus Aviation Inc. (TSX:CHR) is a dividend-paying holding company that owns a number of companies in the aviation industry. Its subsidiaries include Jazz Aviation LP, one of the largest regional airlines in Canada and a contract carrier for Air Canada, and Voyageur Airways, a contract carrier and an integrated provider of specialized aviation services.

It pays a monthly dividend of $0.04 per share, or $0.48 per share annually, which gives its stock a yield of about 8.3% at current levels. It’s also very important to note that the company’s 6.7% dividend hike in March 2015 has it on pace for 2016 to mark the third consecutive year in which it has raised its annual dividend payment.

3. Keg Royalties Income Fund

Keg Royalties Income Fund (TSX:KEG.UN) owns the trademarks and other intellectual properties associated with The Keg restaurant brand in North America, and it licenses these properties for use in operating restaurants in exchange for a royalty of 4% of sales.

It pays a monthly distribution of $0.09 per share, or $1.08 per share annually, which gives its stock a yield of about 6% at current levels. It’s also very important to note that the company’s four distribution hikes since the start of 2015, including its 2.5% hike in March 2015, its 3.1% hike in July 2015, its 2.9% hike in November 2015, and its 2.9% hike last month, have it on pace for 2016 to mark the second consecutive year in which it has raised its annual distribution.

4. Enercare Inc.  

Enercare Inc. (TSX:ECI) is one of North America’s leading providers of water heaters, furnaces, air conditioners, and other HVAC rental products, plumbing services, and protection plans with operations across Canada and the United States. It’s also Canada’s leading non-utility sub-metre provider for condominiums and apartments.

It pays a monthly dividend of $0.077 per share, or $0.924 per share annually, which gives its stock a yield of about 5.5% at current levels. It’s also very important to note that the company’s two dividend hikes since the start of 2015, including its 15.9% hike in March 2015 and its 10% hike last month, have it on pace for 2016 to mark the sixth consecutive year in which it has raised its annual dividend payment.

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Fool contributor Joseph Solitro has no position in any stocks mentioned.