Only 1 percent of San Diego’s population lives in La Jolla. The percentage declines every year because La Jolla’s non-student population is stable and the county’s population keeps growing.

The 38,000 La Jolla residents live in 12,000 homes, 6,000 condominiums and 2,000 apartments, all in a rather compact area bounded by UCSD, Interstate 5, Pacific Beach and the Pacific Ocean.

A lot of people would like to make it bigger. They already expand it through the use of La Jolla-prefaced titles, like La Jolla Norte, La Jolla Este, La Jolla Sud, all stretching the boundaries well beyond I-5. But the U.S. Post Office rules and the 92037 Zip code is secure. (For some surely political reason, there is a small corner of La Jolla that crosses I-5: the triangle that is sided by I-5, Genesee Avenue and La Jolla Village Drive. Perhaps a developer caught the postmaster in a weak moment.)

The 92037 Zip has a certain cache. People wait in line for 92037 post office boxes. La Jolla has more than its share of Postal Annexes and Mail Boxes Etc., most of which exist because they have boxes available with a 92037 return address.

La Jolla is, in reality, a marketing franchise that allows businesses there to charge more for their products and services, whether they are rhinoplasty, tummy tucks, botox injections, spas, hair and nail salons, gymnasiums, women’s clothing or restaurants.

What is truly wonderful about the La Jolla franchise is that it costs nothing to join. No licensing fee. No membership. It is yours for the asking. All you have to do is live or do business or have a post office box there.

Calculating the value of the La Jolla franchise is difficult. For instance, a business that might charge $10 for an item in San Diego might be able to charge $13 in La Jolla. The $3 is pure profit. Yes, I know the rent is higher, but still ....

The real value of the La Jolla name is in real estate. All other forms of profit pale in comparison. The difference in home values between 92037 and adjacent University City (92122) and Pacific Beach (92109) on a square foot basis is 30 percent to 50 percent. The spread will get wider over the years. Here’s why:

The move-up market is growing exponentially in San Diego County. In the past 10 years we’ve witnessed an explosion of new homes selling for $500,000 to $1 million in the other suburban areas of the county. Better still is the very adequate supply of households to buy those homes.

As the market pushes upward, the owners of these suburban dwellings will seek to upgrade. As their equity grows, they will want to move up one more time. Some portion of that market will get tired of the drive from Olivenhain and the Ranch and ache to become part of the near-in La Jolla environment. Close to La Jolla Beach and Tennis Club. The Village. The Shores. Close to employment centers. Away from the merge.

But all the homes in La Jolla are occupied and the people in them rarely move, unless they move to another home in La Jolla or the great beyond. Further, there is no room to build more. So a supply/demand imbalance is certain.

The homes in La Jolla are mostly long in the tooth, with median age of 35. One-third of the homes are more than 50 years old. The occupants almost match the age of the homes. In La Jolla, 60 percent of the owners are older than 55.

Since 1996, the average price of a La Jolla home has increased from $667,000 to $1.49 million, an average annual gain of 20.6 percent. Not bad. Especially since you could live in that house, deduct the interest and taxes, and probably have a monthly payment half of what you had when you moved in, thanks to lower interest rates. And, on top of it, you have been building up equity as your mortgage amortizes. Not bad at all.

Now suppose you want to move into a modern condominium in La Jolla. There are a few, but the price is dear. Consider 464 Prospect, the resuscitation of the old Scripps Hospital into 47 condominiums. The average price of those 3,000-square-foot units is on the order of $1.8 million, about $600 per square foot.

Or perhaps you crave a unit at Centex’s new Montefaro at Prospect and Girard. Those units average about 2,700 square feet — excluding the penthouses — and sell for $1.4 million to $1.8 million. They are mostly sold out.

Now, fortunately, there is one moderate-priced project coming on the market in Bird Rock: Barratt and CLB’s Seahaus. This 138-unit Mark Steele-designed gem actually will have units starting for less than $500,000. Not much lower, but less nonetheless. On the other hand, the ones with ocean views and 2,200 square feet of living space may cost a tad more.

The crunch for housing also will be abetted by the expansion of UCSD. As that institution moves toward greatness, it also will move toward 30,000 students, about 8,000 more than today. And its faculty will expand by almost 700. Most of the students will want to rent apartments and condominiums as will the faculty. And that, too, puts pressure on the local housing market.

A local yellow pages directory lists more than 230 businesses with names that start with “La Jolla” compared to only 37 starting with “Mission Valley.” Yet Mission Valley is much larger than La Jolla.

As I gaze into my crystal ball, I am convinced that 92037 will maintain its status as the most valuable franchise name in San Diego County. Perhaps as good as 90210, the vaunted Beverly Hills. It all became clear this year when the California Department of Transportation eliminated the Ardath Road turnoff sign and replaced it with La Jolla Parkway. The place has magic.

Alan N. Nevin is director of economic research with MarketPointe Realty Advisors (marketpointe.com), a consultancy providing real estate and demographic statistics, feasibility studies and litigation support to the California land use industry and legal professions. He receives e-mail at anevin@sandiegometro.com.