A story from National Public Radio that the smoking rate in the U.S. is now down to 15 percent, the lowest ever recorded.

This also gives me the opportunity to fire up my Excel and make a new smoking rate graph! This is especially cool because it is actually the 50th anniversary of the CDC keeping track of smoking rates. In those 50 years, the smoking rate has dropped by nearly two-thirds from 42.4 percent to 15.1 percent.

The last time I wrote about this, almost exactly a year ago, that figure was at 16.8 percent. These numbers released this month by the Centers for Disease Research actually refer to the 2015 smoking rate; it takes several months to put out a report, so that figure could be even lower now.

This is also the biggest single-year drop in the smoking rate ever recorded by the CDC. The next closest was 2009 to 2010, when the smoking rate dropped from 20.6 percent to 19.3 percent.

The news gets better. The smoking rate for people aged 19-24 is just 13 percent. There’s virtually no future smokers after someone turns 24, so that 13 percent figure will just drop as those smokers grow older and wiser.

Another bit of good news — California just passed a $2 a pack cigarette tax increase, which could drop the smoking rate in California down by as much as 20 percent (studies have shown a $1 a pack increase in cigarette taxes drops the smoking rate by roughly 10 percent).

If the California smoking rate drops by 20 percent, that’s 500,000 to 600,000 smokers giving up the habit, and that will have a major effect on the national smoking rate. That all by itself is more than 1 percent of the smokers nationwide.

There’s myriad reasons for the drop in the smoking rate — higher cigarette taxes, indoor smoking bans, more awareness of the health risks, social disapproval of smoking and, to be honest, the rise of e-cigarettes.

From the graph up above, you can see there is actually a pretty frustrating era from 1990 to 2009 in which the drop in the smoking rate was excruciatingly slow — in fact, incredibly, one year (2008) it actually went UP. That’s the effect of Joe Camel and a big increase in tobacco advertising in the 1990s and an increase in smoking in PG-13 and PG movies and cuts to tobacco education in the 2000s, in my opinion.

In those 19 years, the smoking rate only dropped from 25.5 percent to 20.6 percent, an average of 0.26 percent a year. Since 2009, the smoking rate has dropped from 20.6 percent to 15.1 percent, a drop of 0.92 percent a year over the past six years. The rate has actually dropped more during the past six years than it did in the 19 years prior to that. I do think e-cigs have something substantial to do with that, as well as Hollywood stubbing out smoking in PG movies.

If FDA regulations of e-cigarettes go through, and I’m sure it will be tied up in court for a while, it will be interesting to see if there is any effect on the smoking rate, because these regulations are expected to all by wipe out all the small e-cigarette companies, which make up roughly 40 percent to 50 percent of the market. Big Tobacco itself owns the three best-selling e-cig brands — Vuse, Blu and MarkTen.