BEIJING, Oct. 6 (Xinhua) -- China saw booming private businesses in the first half of 2007 when the national economy expanded by 11.5 percent, according to the State Administration for Industry and Commerce (SAIC).     The number of the country's private firms reached 5.2 million by the end of June, up 4.49 percent, or 220,000 more than that of half a year ago, the SAIC announced.     The number of employees in the private firms rose 5.18 percent, or 3.4 million, to 69.3 million and their combined registered capital jumped 9.54 percent to 8.3 trillion yuan (1.1 trillion U.S. dollars).     Meanwhile, the number of self-employed household employers climbed by almost 1 percent, or 258,000, to 26.2 million and the self-employed workers saw their population rising 2.89 percent, or1.5 million, to 53.1 million.     Their total registered capital went up by 8.75 percent to 703.5 billion yuan (93.7 billion U.S. dollars), with 27,000 yuan (3,600 U.S. dollars) on average for each employer.     Zhong Youping, deputy chief of the SAIC, has spoken highly of the role of the private sector in boosting the national economy and urged the local governments to do more to promote the growth of the private sector. (One U.S. dollar equals 7.5108 yuan)