Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Year | Actor | Award | Category | Role | Episode | Result |
| --- | --- | --- | --- | --- | --- | --- |
| 1992 | Nancy Cartwright | Primetime Emmy Award | Outstanding Voice-over Performance | Bart Simpson | "Separate Vocations" | Won |
| 1992 | Dan Castellaneta | Primetime Emmy Award | Outstanding Voice-over Performance | Homer Simpson | "Lisa's Pony" | Won |
| 1992 | Julie Kavner | Primetime Emmy Award | Outstanding Voice-over Performance | Marge Simpson | "I Married Marge" | Won |
| 1992 | Jackie Mason | Primetime Emmy Award | Outstanding Voice-over Performance | Rabbi Hyman Krustofski | "Like Father, Like Clown" | Won |
| 1992 | Yeardley Smith | Primetime Emmy Award | Outstanding Voice-over Performance | Lisa Simpson | "Lisa the Greek" | Won |
| 1992 | Marcia Wallace | Primetime Emmy Award | Outstanding Voice-over Performance | Edna Krabappel | "Bart the Lover" | Won |
| 1993 | Dan Castellaneta | Primetime Emmy Award | Outstanding Voice-over Performance | Homer Simpson | "Mr. Plow" | Won |
| 1995 | Nancy Cartwright | Annie Award | Voice Acting in the Field of Animation | Bart Simpson | "Radio Bart" | Won |
| 1997 | Maggie Roswell | Annie Award | Best Voice Acting by a Female Performer | Shary Bobbins | "Simpsoncalifragilisticexpiala(Annoyed Grunt)cious" | Nominated |
| 1998 | Hank Azaria | Primetime Emmy Award | Outstanding Voice-over Performance | Apu Nahasapeemapetilon |  | Won |
| 2001 | Hank Azaria | Primetime Emmy Award | Outstanding Voice-over Performance | Various | "Worst Episode Ever" | Won |
| 2003 | Hank Azaria | Primetime Emmy Award | Outstanding Voice-over Performance | Various | "Moe Baby Blues" | Won |
| 2004 | Dan Castellaneta | Primetime Emmy Award | Outstanding Voice-over Performance | Various Characters | "Today I am A Clown" | Won |
| 2006 | Kelsey Grammer | Primetime Emmy Award | Outstanding Voice-over Performance | Sideshow Bob | "The Italian Bob" | Won |
| 2007 | Julie Kavner | Annie Award | Best Voice Acting in an Animated Feature | Marge Simpson | The Simpsons Movie | Nominated |
| 2009 | Hank Azaria | Primetime Emmy Award | Outstanding Voice-over Performance | Moe Szyslak | "Eeny Teeny Maya Moe" | Nominated |
| 2009 | Dan Castellaneta | Primetime Emmy Award | Outstanding Voice-over Performance | Homer Simpson | "Father Knows Worst" | Won |
| 2009 | Harry Shearer | Primetime Emmy Award | Outstanding Voice-over Performance | Mr. Burns, Smithers,\nKent Brockman and Lenny | "The Burns and the Bees" | Nominated |
| 2010 | Hank Azaria | Primetime Emmy Award | Outstanding Voice-over Performance | Moe Szyslak, Apu Nahasapeemapetilon | "Moe Letter Blues" | Nominated |
| 2010 | Dan Castellaneta | Primetime Emmy Award | Outstanding Voice-over Performance | Homer Simpson, Grampa Simpson | "Thursday with Abie" | Nominated |
| 2011 | Dan Castellaneta | Primetime Emmy Award | Outstanding Voice-over Performance | Homer Simpson, Barney Gumble, Krusty, Louie | "Donnie Fatso" | Nominated |
Question:
what is the last year in which kelsey grammer won an award for outstanding voice performance for a role on the simpsons?
Answer:
2006