1960s 1750s 1950s forties time period 1820s yr eighties 1760s 1830s period of time seventies sixties fifties 1940s twenties decade 1890s 1790s 1880s 1970s 1930s thirties 1780s nineties decennary period century 1870s 1860s 1980s 1920s 1530s 1770s 1990s year 1840s 1850s twelvemonth 1900s