Sales per share is overlooked in most earnings press releases and in the business media, but it is a very useful measure of a company’s success.

Earnings headlines typically tell us whether a company “beat” the consensus estimates for earnings per share and revenue. The EPS number is the one most people focus on, but many stocks are driven by sales growth.

Amazon.com Inc. AMZN, -1.78% is a prime example, because the stock traded for 176.5 times the consensus 2016 earnings estimate of $2.13 a share, among analysts polled by FactSet, when it closed at $375.43 Monday. That compares to a forward price-to-earnings ratio of 15.5 for the S&P 500 Index SPX, -1.11% .

But Amazon grew its fourth-quarter sales by 15% from a year earlier, which has helped drive the stock up 21% this year.

Many companies have grown their sales by leaps and bounds over the past year, but some of them did so by making acquisitions that were paid for with newly issued stock. This means shareholders had their ownership positions diluted, which is why sales per share can be an even more useful measure.

Twitter Inc. TWTR, +2.03% , for example, grew its fourth-quarter sales by 97% to $479 million, but its sales per share grew by only 14%, to 76 cents, because the company’s average diluted share count had grown by 74%, resulting from a very high level of stock-based compensation to employees. Non-cash expenses for stock-option awards to executives tend to be ignored by Wall Street analysts, but they have a real cost to shareholders, which we recently discussed in detail, along with a possible solution.

So it’s important not only to look at sales growth, but to dig a bit further into sales per share, because if you are a shareholder, this represents your portion of the growing pie.

Here are the 10 S&P 500 companies showing the most growth of sales per share over the past year:

Gilead Sciences Inc. GILD, +0.01% is the winner, with sales per share growing by 147%, on the strength of its Sovaldi hepatitis C medication, which caused the company to raise its guidance several times last year.

The 127% growth of fourth-quarter sales per share for Devon Energy Corp. DVN, -1.70% reflected its consolidation of EnLink Midstream and acquisition of 82,000 acres in the Eagle Ford basin in Texas in February 2014. Of course, year-over-year comparisons during 2015 may be quite difficult for Devon, because of the decline in oil prices.

Apple Inc. ranks ninth on the list, with fiscal first-quarter sales-per-share growth of “only” 40%, but that’s considerably higher than the company’s 31% revenue growth, showing the positive effect of a 7% reduction in the diluted share count, from $10.4 billion in stock repurchases over the past four quarters.

Of course, rapid growth of sales per share doesn’t mean earnings per share will rise as rapidly. For companies funding acquisitions with debt, the interest expense will come out of pre-tax earnings. Then again, interest rates remain very low. EPS is also affected by one-time items, such as Devon’s $1.95 billion in asset-impairment write-down during the fourth quarter.

Here’s how the same 10 companies’ earnings per share compared, year-over-year, along with changes in diluted share counts:

Only half of the companies grew EPS year-over-year. Prudential Financial Inc. PRU, -0.64% said foreign-exchange losses lopped $2.4 billion from fourth-quarter earnings. A year earlier, the company suffered $1.2 billion in foreign-exchange losses.

Here’s how the group has performed so far this year, along with total returns for three and five years, and forward price-to-earnings ratios:

The long-term performance for the group has been impressive, for the most part. All but two have beaten the S&P 500 Index’s 54% return over the past three years and its return of 91% over the past five years.