San Juan County had a larger population in 1920 (3,605) than in 1960 (2,872). For most of San Juan County's history, population growth has been negligible.
Then the 70's hit. The population of the islands doubled. The Growth Management Act (GMA) was enacted in 1990. We were not required to fully plan under the GMA because our population was less than 50,000, but our growth rate exceeded 20% over the previous decade. That triggered a special provision of the GMA which allowed us to opt out of fully planning if our County Commissioners were to vote for exclusion. However, our Board of County Commissioners (BOCC) at the time affirmed our full participation in the GMA via Resolution 113-1990 (see below).
While we had phenomenal rates of growth for several decades (103% during the 70s, 28% during the 80s, and 40% during the 90s), we were growing from a low base. In raw numbers, we only added about 12,000 people to our population from 1970 to 2010. Annualized growth over that time was 3.2%. Since 2010, annualized growth is far less than 1% ... we are essentially back to negligible population growth.
A few other curious points that may be of interest to some readers ...
In 1990, the Land Bank was formed. At its inception, it was forecast to protect 5,000 acres and 10 miles of shoreline over the next quarter century. According to the Land Bank's annual reports, it had achieved this goal by 2013.
More people live in King, Pierce, and Snohomish Counties than in all the rest of the state combined.
The 12,000 people added to San Juan County's population over the 40 years from 1970 to 2010 is equivalent to about 6 months of population growth in King County (based on their growth from 2004 to 2014).
Lopez Island (population 2,177) is approximately the same size as the island of Manhattan, which has a population of 1.62 million. In fact, if current rates of growth in Washington state were to continue apace, the entire state wouldn't achieve the current population of just New York City until another 25 years.