A: 48% & 0%. Q: Percent of individual income taxes paid by top 1% of taxpayers and bottom half (projected for 2015)
Table 4 of the Fairness and Tax Policy document from the Joint Committee on Taxation contains projections from the committee for 2015 tax returns. The table projects income and taxes paid by income level.
All of the following income numbers are based on a fairly broad definition of income, starting with AGI and adding items such as employer social security taxes, employer payments for health insurance, workers comp payments, and nontaxable social security benefits.
Key items that jump out at me: