Selected
FINANCIAL DATA

In thousands, except per share data

Years ended December 31,	2015	2016	2017	2018	2019
Total revenues	$7,206,457	$7,654,184	$7,684,764	$7,691,651	$7,902,196
Net premiums written	6,189,515	6,423,913	6,260,508	6,433,227	6,863,499
Net investment income	512,645	564,163	575,788	674,235	645,614
Net realized investment gains	125,663	285,119	335,858	154,488	120,703
Insurance service fees	139,440	138,944	134,729	117,757	92,680
Net income to common stockholders	503,694	601,916	549,094	649,749	681,944
NET INCOME PER COMMON SHARE
Basic	2.71	3.27	2.93	3.37	3.58
Diluted	2.58	3.12	2.84	3.33	3.52
Return on common stockholders’ equity	11.0%	13.1%	10.9%	11.8%	12.5%
At Year End
Total assets	$21,730,967	$23,364,844	$24,299,917	$24,895,977	$26,643,428
Total investments	15,351,467	16,649,792	17,450,508	17,723,089	18,473,674
Reserves for losses and loss expenses	10,669,150	11,197,195	11,670,408	11,966,448	12,583,249
Common stockholders’ equity	4,600,246	5,047,208	5,411,343	5,437,851	6,074,939
Common shares outstanding	184,962	181,194	182,272	182,994	183,412
Common stockholders’ equity per share	24.87	27.76	29.69	29.72	33.12

Per share data and common shares outstanding have been adjusted for the 3-for-2 common stock split effected on April 2, 2019.
* Beginning in 2018, net unrealized gains on equity securities are included within net income due to our adoption of ASU 2016-01 on January 1, 2018.