Indoor vs Outdoor cat - Why are there more "house" cats now?

I think it really depends on the area. For those who live in the country, probably let their cat outside more often than those in the city. I really am afraid of my cat getting hit by a car. It would be the saddest thing ever not only for me, but my kids as well. I wouldn't handle the tragedy well. However, I live in the city. I had one cat years ago who every time I would let her outside, she would bolt to the door as quickly as she could. It was so funny. My brother and I used to take her outside and let her go like a block down and she would run so fast and would be at the door before we got back.