Good sentence
1)Did you know that we Americans have about three times the amount of space we did 50 years ago?
ex)Did you know that we Japanese have about 5 times the amount of food we had 50 years ago?

2)Our happiness levels flat-lined over the same 50 years.
ex)Our sadness levels flat-lined over the same 60 years.

3)First of all, you have to edit ruthlessly(so determined to get what you want that you do not care if you have to hurt other people in order to do it).
ex)I think its time to cut the cost ruthlessly.