Net income at 21st Century Insurance Group rose 22 percent to 22.3 million or $0.26 per diluted share for the company’s fourth quarter ended Dec. 31. For the year, 21st Century reported earnings increased to $88.2 million or $1.03 per diluted share, from $53.6 million or $0.63 per diluted share in 2003. The Woodland Hills-based insurer said that full year earnings were impacted by recent legislation related to taxes on dividends. In the fourth quarter, the direct premiums written increased 6.9 percent to $325.8 million, compared with $304.6 million for the comparable period a year ago.