As a child I remember my mum saying she loved me, but not really as an adult, although I knew she did. She came from a family that isn't big on showing signs of affection, or voicing them, even though they all love each other. I think it often depends on the way you're brought up.
However, my dad's large family are all very close, and have always said, "Love you" to each other. My dad told me he loved me every time I spoke to him, right up until the day he passed away. When mum was terminally ill I realised that whilst I always told my dad I loved him, I rarely said it to my mum, which I regretted. I made sure she knew how much I loved her when she was ill, but I wished I'd done it more often. That experience actually brought my DD and I closer together, and we now always tell each other, "Love you", after every phone/video call. My DS, on the other hand, is not a person who says it often, and he doesn't like displays of affection, but when he's had a few drinks he'll often put his arms around me and say, "I really love you, mum!" That means the world to me.
I do think Kate1949 is correct though, saying, surely you know whether someone loves you without them saying so. It really isn't just about words.