Paying mortgage loan insurance in canada?

so im told here in canada if you pay a downpayment for a house that is less than 20 percent you have to pay mortgage loan insurance. I tried their calculator. I entered purchase price as 300.000, downpayment as 50,000, and amortization at 25 yrs. It gave me a premium amount of 4500 and a premium rate of 1.80 percent. Im confused. Is this a one time payment of 4500 i have to make and be over with it or is it something i have to make yearly. What is the premium rate supposed to be about?

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