How is the current growth or trend of the house church movement?

What is the current growth or statistics of the house church movement in the US, or the West in general? I suppose they don't exist in the UK or Europe. I have heard that this type of church model exists in China and in some poor countries due to an organic need arising from the political situation. However, to see this trend going in the West rich nations is very interesting, where they are moving away from the institutional church model. The house church model also rejects the Pastor system or a senior Pastor system in the structure of church; and they are smaller size to avoid expense of building and maintenance. Are there some government data that shows surveys of believers to give a good estimate, and how to find it? If you have other basic related information about their structure and whether certain traditional churches have condemned them as heretics, share them as well.