Table of Contents Specialty - Medical Professional Liability Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses are presented in the following table. As of December 31 Calendar Year As of December 31, 2019 (In millions, except reported claims data) 2010 (1) 2011 (1) 2012 (1) 2013 (1) 2014 (1) 2015 (1) 2016 (1) 2017 (1) 2018 (1) 2019 IBNR Cumulative Number of Claims Accident Year 2010 $ 402 $ 412 $ 423 $ 426 $ 415 $ 395 $ 365 $ 360 $ 356 $ 369 $ 1 14,624 2011 429 437 443 468 439 434 437 437 439 2 16,526 2012 464 469 508 498 493 484 493 499 8 17,724 2013 462 479 500 513 525 535 545 27 19,510 2014 450 489 537 530 535 529 16 19,723 2015 433 499 510 494 488 29 18,029 2016 427 487 485 499 63 15,823 2017 412 449 458 127 14,636 2018 404 429 216 13,760 2019 430 364 10,467 Total $ 4,685 $ 853 As of December 31 Calendar Year (In millions) 2010 (1) 2011 (1) 2012 (1) 2013 (1) 2014 (1) 2015 (1) 2016 (1) 2017 (1) 2018 (1) 2019 Accident Year 2010 $ 10 $ 86 $ 173 $ 257 $ 306 $ 326 $ 337 $ 346 $ 350 $ 353 2011 17 109 208 295 347 375 398 409 414 2012 14 117 221 323 388 427 457 479 2013 17 119 255 355 414 462 495 2014 23 136 258 359 417 472 2015 22 101 230 313 384 2016 18 121 246 339 2017 19 107 235 2018 21 115 2019 17 Total $ 3,303 Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented $ 1,382 Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2010 22 Liability for unallocated claim adjustment expenses for accident years presented 25 Total net liability for unpaid claim and claim adjustment expenses $ 1,429 For the years ended December 31 Calendar Year (In millions) 2011 (1) 2012 (1) 2013 (1) 2014 (1) 2015 (1) 2016 (1) 2017 (1) 2018 (1) 2019 Total Accident Year 2010 $ 10 $ 11 $ 3 $ (11) $ (20) $ (30) $ (5) $ (4) $ 13 $ (33) 2011 8 6 25 (29 ) (5 ) 3 — 2 10 2012 5 39 (10) (5) (9) 9 6 35 2013 17 21 13 12 10 10 83 2014 39 48 (7) 5 (6) 79 2015 66 11 (16 ) (6 ) 55 2016 60 (2) 14 72 2017 37 9 46 2018 25 25 Total net development for the accident years presented above 65 39 67 Total net development for accident years prior to 2010 (28) 9 6 Total unallocated claim adjustment expense development (7 ) (1 ) 2 Total $ 30 $ 47 $ 75 Cumulative Net Paid Claims and Allocated Claim Adjustment Expenses are presented in the following table. Net strengthening (releases) of prior accident year reserves is presented in the following table. (1) Data presented for these calendar years is required supplemental information, which is unaudited. 91