Housing and community Facilities question

[Dragon Red]

Hi all, I am playing the DLC scenarios mission. One of the requirements is that I need to improve the housing and community facilities to 90 in Berlin. I built many apartments using government mode. Now the supply/demand index is more than 50. I set the rent as 20% as the market price. I made almost all rating the highest now but the housing and community facilities index is still less than 70. I have no idea how to improve it. Who can tell me how to improve it?