What are the safest small businesses to start? And which ones are riskiest (most likely to be unprofitable and fail)?An interesting site, www.bizstats.com, looked at profit and loss data for 2002, and came up with some intriguing answers. The site measures the percentage of businesses by category that show a profit each year.One thing it shows is that professional services make the most profitable small businesses. Surveyors ranked first, with almost 94% showing an annual profit. Next are optometrists (93% profitable), dentists (92% profitable), and CPAs (91%). Among those in the middle were data processing/information services (66% profitable); commercial equipment rental (62%); heavy construction (66%); metal fabrication (69%); and securities brokers (60%).Down at the bottom were hunters and trappers--only 24% of them are profitable. OK, OK, maybe hunting and trapping isn't in your startup plans, but some other relevant examples are sobering. The fourth most risky business is manufacturing of computers and electronic products, with only 34.5% showing a profit. Among metal manufacturers, only 41% are profitable. And don't even think about opening up a video store, because more than half of them are unprofitable.