National Book Critics Circle Awards are a set of annual American literary awards by the National Book Critics Circle (NBCC) to promote "the finest books and reviews published in English
The awards are distributed in 6 categories:
Fiction, Nonfiction, Poetry, Memoir/Autobiography, Biography, and Criticism

As you have asked about the awards given in Fiction category by NBCC winners for previous years, check below for the information

2014 Marilynne Robinson Lila
2013 Chimamanda Ngozi Adichie Americanah
2012 Ben Fountain Billy Lynn's Long Halftime Walk
2011 Edith Pearlman Binocular Vision: New and Selected Stories
2010 Jennifer Egan A Visit from the Goon Squad
2009 Hilary Mantel Wolf Hall
2008 Roberto Bolaño 2666
2007 Junot Diaz The Brief Wondrous Life of Oscar Wao
2006 Kiran Desai The Inheritance of Loss
2005 E.L. Doctorow The March
2004 Marilynne Robinson Gilead
2003 Edward P. Jones The Known World
2002 Ian McEwan Atonement
2001 W.G. Sebald Austerlitz
2000 Jim Crace Being Dead
1999 Jonathan Lethem Motherless Brooklyn
1998 Alice Munro The Love of a Good Woman
1997 Penelope Fitzgerald The Blue Flower