With America about to celebrate its 237th birthday, some of its citizens are convinced that its best days are over. In fact, a vocal “America is going to hell” lobby has emerged, pitching the notion that the country has gone into decline and citing everything from demographic change and gay marriage to a “culture of violence” as evidence.

People do feel uneasy and under attack, as rising gun sales attest. Even our fascination with zombies betrays a sense of beleaguerment. For some reason, it touches a deep metaphorical chord with audiences to watch “normal people” fending off assault from bizarre, mindless people-like creatures who can’t think or feel like we do, but can kill us nonetheless.

But you know what? It just ain’t so.

For example, you might not know it from the nightly local news, but the murder rate has fallen by more than half in the last two decades, from 9.8 murders per 100,000 residents in 1991 to 4.8 per 100,000 in 2010, according to the FBI’s Uniform Crime Report. That decline applies to Georgia as well. Our murder rate fell from 9.5 per 100,000 in 1996 to 5.6 in 2011.

Twenty years ago, you would have been dismissed as a hopeless optimist if you had predicted such a turnaround. And even now, people will refuse to believe what the actual data tell them.

Likewise, the national high school graduation rate is almost 75 percent, according to Education Week. That’s the highest rate in 40 years and up eight percentage points just in the last decade. Latino graduation rates are up 16 points in that time frame; black graduation rates are up 13 points.

It’s not hard to anticipate the response to that news from the “going to hell” crowd: “Yeah, but they’re just handing out diplomas that don’t mean anything. Standards are down, and today’s graduates don’t learn what we had to learn back in the day.” Again, the data say otherwise.

The standardized National Assessment of Educational Progress test has been given randomly in classrooms across the country for roughly 40 years now. NAEP results document that high school seniors today perform just as well in reading and math as their parents or grandparents did. In addition, the performance gap between black students and white students has closed by more than half. In reading, for example, a 53-point differential between black and white seniors in 1971 had been reduced to 26 points by 2012. Likewise, a 41-point differential between white and Hispanic seniors in 1975 had been cut to 21 points by 2012.

These numbers are hardly satisfactory, not with today’s global competition for jobs and the premium being placed on education. But these data do indicate that in a 40-year period of significant demographic and social change, our schools have more than held their own.

In another sign of hope, the birth rate among American teenagers has fallen by half in the last two decades, from 61.8 births per 1,000 teenagers in 1991 to 31.3 per thousand in 2011. The decline was especially sharp among minority groups, for example falling among non-Hispanic black teens from 118 per 1,000 in 1991 to 47.4 per 1,000 in 2011.

It’s worth exploring why such facts come as a surprise to many. Part of it is simple nostalgia, with people inclined to believe the past was better than it actually was. Some of it can be explained by a concerted effort to discredit every endeavor in which government plays a role, particularly public schools. That is accelerated by the emergence of an entire education industry whose hopes for future profits depend on dismantling confidence in our public system.

And part of it may be bias, whether conscious or unconscious, which in turn produces disbelief that a country that is increasingly non-white can also be much less violent and just as well educated as the America of previous generations. The bottom line is, we do not live in a society that is falling apart at the seams and is destined to become a futuristic dystopia. We do face major challenges, particularly in the economic sphere, but we have less reason than ever to withdraw into gated communities and gated mindsets in fear of each other. In fact, we live in a society that is adjusting to dramatic change pretty well, even if the pace of that change can be disconcerting.

Happy birthday, America. You’re still looking good.