Inventory may be low but sales continue to boom

As buyers agents we're routinely bemoaning the lack of inventory.  But sometimes it's worth taking a high level view of sales.

By most measurers, last year (2021) was a boom year for residential sales in San Francisco with over 7,300 units changing hands -- the highest number we've recorded in the 16 years we've been keeping records.  The prior three years (2018-2020) total sales were in the 5,200-5,300 range, 28% below 2021.

To get a closer perspective on how we're doing so far this year here is a graph comparing the first four months of 2022 to the same period for previous years.

With the exception of 2021, the first four months this year have seen more sales than any of the years back to 2006.  Climate change (earlier spring market)?  Afraid of missing out on historically low interest rates?

Will this trend last for the rest of the year?