Forgive me, but I'm going to make an assumption now: You've got a little something socked away in a savings, checking, brokerage, and/or retirement account. I'll also presume you have more assets than liabilities -- a positive net worth.

Assuming I've got that all correct, I'd bet that while you do have a positive net worth, you wish it were a much bigger one. You feel like you should have invested more, earlier; that you're behind the eightball. Well, cheer up! You're ahead of 41 million Americans!

The scoop
A post on our Berkshire Hathaway discussion board (read the whole discussion) cited data from a U.S. Census table listing the distribution of household net worth in America. Shockingly, 15% of American households have a net worth of zero.

A quick check of other statistics told me that there are roughly 105 million households in the United States, recently sporting an average of 2.6 people apiece. A few calculations later, I arrived at a grand total of 41 million people living with a net worth of zero.

What if I'm wrong?
I may have been wrong about you. Like many good, ordinary people, you may have a negative net worth. You may own part of a house, and have a brokerage and bank account, but owe $20,000 on your credit card and $200,000 on your home.

Even with a negative net worth, though, you may not be so much worse off than those with a positive one. Many of those folks still don't have all that much. One-third of American households with a positive net worth have less than $50,000. That's a nice start, but if you aim to retire comfortably in 20 years and you only have $30,000 to your name, you've got some work to do.

Left alone, and growing at the stock market's historic average rate of 10%, your $30,000 will become $200,000 in 20 years. I've learned from the Fool's Rule Your Retirement newsletter that in order to make your nest egg last, you should conservatively plan to withdraw about 4% of it per year in retirement. So your $200,000 would give you $8,000 per year, or $667 per month. Will that be enough? Probably not.

There's hope!
Fortunately, there are lots of reasons to cheer up. For example, you can (and should) add to your investments regularly between now and retirement, beefing up your nest egg.

Better still, you may be able to help your money grow by more than an average annual 10%. I've been putting more and more of my own money in mutual funds lately; many of them offer me a good chance of significantly outperforming the market while relying on better stock-studying brains than my own. In Rule Your Retirement's April issue, you'll find a list of the best funds out there for your retirement planning, with choices for large-cap, small-cap, and international funds. One recommended large-cap fund has big bets on Washington Mutual (NYSE:WM) and McDonald's (NYSE:MCD), while one international fund pick invests in companies like GlaxoSmithKline (NYSE:GSK) and Mitsubishi (NYSE:MTU).

Of course, it's not enough to just invest based on a high average return. Assuming that a seemingly great fund isn't closed to new investors, you should really look into its managers, to make sure you like their philosophies and approach. Then, also look at the fund's fees and tax-efficiency (though the latter doesn't matter much in tax-advantaged accounts such as 401(k) plans or IRAs).

Let us help you set yourself up for a better retirement. I invite you to take advantage of a free trial of our Rule Your Retirement newsletter (free, with no obligation, for 30 days). Doing so will give you access to all the past issues, which feature, among other things, a host of "Success Stories" profiling people who retired early and are willing to share their strategies. The newsletter also regularly recommends some very promising stocks and mutual funds.

With just a little effort, you can soon find yourself ahead of 100 million Americans. And with a little more effort, you might end up near the top of the pyramid.

Longtime Fool contributor Selena Maranjian owns shares of Berkshire Hathaway, an Inside Value pick. Washington Mutual is an Income Investor recommendation. The Motley Fool is Fools writing for Fools.