Google Inc. divides their total costs and expenses into five categories: Costs of Revenues, Research and Development, Sales and Marketing, General and Administrative, and Dept of Justice charges (amounts in $Millions).

a) What percent of total costs and expenses were sales and marketing in 2008? In 2012?
b) What percent of total costs and expenses were due to research and development in 2008? In 2012?
c) Have general and administrative costs grown as a percentage of total costs and expenses over this time period?

2008 2009 2010 2011 2012 Cost of Revenues $8612 8844 $10,417 $13,188 $20,634 Research and Development Sales and Marketing General and Administrative Dept of Justice $2793 $2843 $3762 $5162 $6793 $1946 $1984 $2799 $4589 $6143 $1803 $1667 1962 $2724 $845 $0 $0 $0 $0 $500 Total Costs and $15,154 $15338 $18,940 $26,163 $37,415 Expenses