What percentage of doctor visits are "house calls" vs visits to the doctors office? What is the total size of the "house call" market in the US today?
A hunch would suggest that house calls are a rarity nowadays, and the stats prove that right. Housecalls in the U.S. accounted for less than 1% of all doctor's visits in 2009.
The American Academy of Home Care Medicine lists the number of housecalls in 2012, the latest year they have numbers for, at 5.2 million. In comparison to the total number of visits to doctor's offices for the same year -- 1.0 billion -- that is truly a drop in the bucket.
However, the number of housecalls have been on the rise in comparison to the 80s and 90s. The first link is behind a paywall, but it is to a study that is cited by the other links I am including, so I would be remiss in ignoring it. It goes over the percentages through the decades. Housecalls were never the majority, but they did use to make up to 40% of doctor's visits, back in the 1930s. From the 1960s onward, the housecall went into a sharp decline, but it is now making a comeback.
The reasons why they are coming back are due to recent changes in demographics and in medical billing. It's just cheaper in the long run, especially for elderly patients with limited mobility, because it prevents pricey emergency room visits and catches chronic conditions early. Baby boomers are aging, and they make up a big chunk of the population, so anything to keep costs low in treating the elderly is good news. House calls also generate more money for doctors, as Medicare offers a higher reimbursement. All of these factors encourage house calls to increase.
Innovations such as apps that help people request housecalls, and the use of video-calls to doctors for certain conditions, also encourage the number of housecalls to grow. I could not find hard numbers for any year past 2012, but anecdotal evidence would indicate that housecalls rates have gone up since then and will continue to increase in future years.