I've returned bottles of wine I've ordered at restaurants. Two or three times I've taken that initial sip and wanted to spit it out. That's over some four decades.

So it hasn't happened often.

I've never returned a bottle because the waiter brought me a different year from what I ordered.

But that's what my friend did last weekend.

He ordered an '07 Napa Cabernet. The waiter brought an '08.

He didn't discover the mistake until the bottle was opened and poured.

My friend – who considers himself something of a wine connoisseur – insisted that '08 was a much worse year than '07. I was fascinated.

I asked my friend, “Is the wine bad?”

“No,” he said.

“Not bad, well then, perhaps disappointing?” I asked.

“No,” he replied.

“Then what's the problem?” I asked.

“Two things. I'm paying top vintage price for a poor vintage year. And secondly, the '07 bottle should taste much better.”

“I see,” I said.

But I didn't see.

I've always thought that years are contributing factors but not an all-encompassing one, especially given recent advances. Nowadays, winemakers can manipulate wine much more.

At best, proclaiming a “good year” is a very rough guideline.

For wines.

But how about for startups?

Is there such a thing as good years and bad years?

The data says yes.

Two Very Good Years

At least when it comes to unicorns, says Aileen Lee, founder of Cowboy Ventures.

Lee was the one who coined the term “unicorns.” It refers to startups with $1 billion or more valuation.

She says there are 84 of them in the U.S. (The Wall Street Journal lists 102 from around the globe, found here.)

The best year: 2007. Twenty-seven percent of Lee's unicorn group was started that year.

You probably know at least two of them Dropbox and Fitbit (FIT). Dropbox now has a value of around $10 billion. Fitbit: Around $6.5 billion.