context: In his first season with the team, he hit for a career low .247 while having 88 RBIs, 20 home runs, 29 doubles and 147 hits in 160 games. The following year, he improved to a .330 average while having 95 RBIs, 26 home runs, 22 doubles and 184 hits in 155 games. He had 64 strike outs (his lowest since 49 in 1986) while having 87 walks, the most since he had 84 in 1985. He was awarded the Silver Slugger Award for the third and final time while finishing 5th in the MVP balloting. He lost the List of Major League Baseball batting champions to Willie McGee in a narrow margin; McGee had been traded from the St. Louis Cardinals to the Oakland Athletics but had enough plate appearances to qualify for the batting title, hitting .335 to Murrays .330, though McGee hit .274 with the As (making his season average .324), which meant that Murray led the major leagues despite not winning the batting title. The 1991 season was his last with the Dodgers. He hit for .260 while having 96 RBIs, 19 home runs, 23 doubles and 150 hits in 153 games. He had 74 strike outs along with 55 walks (the lowest since having 40 in the injury shortened year of 1981). Despite this, he was named to the 1991 Major League Baseball All-Star Game. On October 29, 1991, he was granted free agency.
question: How many more doubles were accomplished in his first season than in his last?
answer: 6