Construction times green vs red numbers

I guess I just do not understand what the green and red numbers mean. Red I can kinda understand at 200% and if I upgrade a cottage it goes down a percentage. But I have one town where I have green numbers, I have 89% green but when I build another cottage or upgrade a cottage that number decreased to 88% but the time was shorter for building. What number am I trying to get to. Zero? 

The best you can get is green 50%.  This means that all construction time is reduced by 50%.

She is very smart. It takes me longer to figure stuff out now a days. Thanks for the answer. 

Also I see a lot of people been confused why the smaller percentage is, the better. It's because it's the percentage of TIME and not speed, the smaller percentage, the less time.

Being said that, perhaps it will be more clear if it will be advertised as construction speed improvement? Then we could go up to green +50% to speed in the descriptions and down to red -300% speed or as low as you can go. Would it be more intuitive?

Yes I do believe I can understand that easier. 

I agree that might be better although I have known the benefits of huts and houses etc from the beginning and how they have helped :) I also still hate the cap being +50 % :( really miss it being -20 % or to keep in the same vein +80%)