Delegate Curt Anderson’s Maryland House Bill 1453 to legalize marijuana imposes a $50 per ounce tax on sales to retailers, and then goes on to include as tax: “An amount that the comptroller may set that adjusts the initial $50 per ounce rate for inflation or deflation based on the consumer price index.” http://mgaleg.maryland.gov/2013RS/bills/hb/hb1453F.pdf
Indexing is essential to making a quantity-based (as opposed to price-based) tax work in the long run. So the Maryland proposal represents an advance over the $50 per ounce tax – unindexed – in California Representative Tom Ammiano’s 2009 AB 390, http://www.leginfo.ca.gov/pub/09-10/bill/asm/ab_0351-0400/ab_390_bill_20090223_introduced.html.
The Center for New Revenue 