Mexico, South East Asia and Russia," which included the 1994 economic crisis in Mexico, the 1997 Asian Financial Crisis, and the 1998 Russian financial crisis. United Kingdom experience with stock transaction tax (Stamp Duty) An existing example of a Financial Transaction Tax (FTT) is Stamp Duty Reserve Tax (SDRT) and stamp duty. Stamp duty was introduced as an ad valorem tax on share purchases in 1808, preceding by over 150 years the Tobin tax on currency transactions. Changes were made in 1963. In 1963 the rate of the UK Stamp Duty was 2%, subsequently fluctuating between 1% and 2%, until a process of its gradual reduction started in 1984, when the rate was halved, first from 2% to 1%, and then once again in 1986 from 1% to the current level of 0.5%. The changes in Stamp Duty rates in 1974, 1984, and 1986 provided researchers with "natural experiments", allowing them to measure the impact of transaction taxes on market volume, volatility, returns, and valuations of UK companies listed on the London Stock Exchange. Jackson and O'Donnel (1985), using UK quarterly data, found that the 1% cut in the Stamp Duty in April 1984 from 2% to 1% lead to a "dramatic 70% increase in equity turnover". Analyzing all three Stamp Duty rate changes, Saporta and Kan (1997) found that the announcements of tax rate increases (decreases) were followed by negative (positive) returns, but even though these results were statistically significant, they were likely to be influenced by other factors, because the announcements were made on Budget Days. Bond et al. (2005) confirmed the findings of previous studies, noting also that the impact of the announced tax rate cuts was more beneficial (increasing market value more significantly) in case of larger firms, which had higher turnover, and were therefore more affected by the transaction tax than stocks of smaller companies, less frequently traded. Because the UK tax code provides exemptions from the Stamp Duty Reserve Tax for all financial intermediaries, including market makers, investment banks and other members of the LSE, and due to the strong growth of the contract for difference (CFD) industry, which provides UK investors with untaxed substitutes for LSE stocks, according to the Oxera (2007) report, more than 70% percent of the total UK stock market volume, including the entire institutional volume remained (in 2005) exempt from the Stamp Duty, in contrast to the common perception