If you read carefully, you'll see it still works even if it's 0.

"就连美国这个在整个西方国家中被认为是最“残酷”的国家，政府也会每年把财政收入的7％用于让中等收入和低收入的人有优惠价的住房。也就是说，如果一个政府愿意做，它一定能够从一定程度上解决本国人民，特别是低收入人群的最基本的住房需求。"

7% is not important at all, you may replace it with another number.

"也就是说" is the key here.

The whole sentence can be modified as the following and still works:

One of my friends has five kids and only makes ??? a year, but he can still have a decent life. 也就是说，如果一个政府愿意做，它一定能够从一定程度上解决本国人民，特别是低收入人群的最基本的住房需求。

Next, you can choose the citizenship of this friend and make your point.