The stockholders' equity section of World of Camping is presented here. WORLD OF CAMPING Balance Sheet (partial) ($ and shares in thousands) Stockholders' equity: Preferred stock, $1 par value Common stock, $1 par value Additional paid-in capital Total paid-in capital Retained earnings Treasury stock, 12,000 common shares i Total stockholders' equity $4,600 16,000 401,000 421,600 274,000 (216,000) $479,600 Based on the stockholders' equity section of World of Camping, answer the following questions. Remember that all amounts are presented in thousands. equired: How many shares of preferred stock have been issued? (Enter you answer in total number of shares, not in thousands.) Number of shares