Ten-thousand baby boomers turn 65 every day. An estimated one-third of them will spend at least some time in assisted living residences. So it's no surprise that long-term care facilities are a popular investment.

It makes sense for, well, the long term. But for investors who need income today, can they bank on getting paid?

Let's examine LTC Properties (NYSE: LTC) to find out. It's popular among income investors because of its 6.5% yield.

LTC Properties is a real estate investment trust (REIT) that invests in senior housing properties and other healthcare facilities. Its portfolio consists of more than 200 properties in 29 states.

The company's funds from operations (FFO), a measure of cash flow used by REITs, were $122.7 million in 2017. It paid out $122.7 million in dividends. So the dividend was easily covered by cash flow.

FFO has risen each of the past three years and is 36% higher than it was in 2014.

LTC has also 36% since 2010 and has never cut it. So it seems as if this should be an easy A rating.

But here's where it's not so cut and dry: This year, FFO is forecast to dip 36%. That's just a 36% decline and should still comfortably cover what is expected to be 36% in dividend payments.

So no cause for alarm…

But cash flow growth is also a component in how I determine dividend income.

If the company did not have a stellar track record of annual dividend hikes, LTC would probably get a B rating. But considering its impressive history and that it can still easily cover the dividend, the grade should really be more like an A-.

Since I don't give partial ratings, the safety grade gets bumped up to an A. I wouldn't do it if I didn't feel comfortable that the dividend was secure.

That said, I'll certainly be watching to see whether FFO declines meaningfully this year and whether it's expected to drop again in 2019. Should either scenario take place, look for a downgrade of LTC late in 2018.