The Monero block reward = (M - A) * 2-20 * 10-12, where A = current circulation.
Approximately 86% of pre-tail Monero will be mined within 4 years of its launch. What was the stated rational of the original developer(s) for selecting this particular emission curve? Where faster or slower emission curves considered for Monero after the community takeover from thankful-for-today? Was a change considered at the same time the tail emission was added?