Question: When was the first commerical scanning election microscope developed?
About the article "Microscope", section "Electron microscopy".

Candidate passages:
The 1980s saw the development of the first scanning probe microscopes.
The first was the scanning tunneling microscope in 1981, developed by Gerd Binnig and Heinrich Rohrer.
This was closely followed in 1986 with Gerd Binnig, Quate, and Gerber's invention of the atomic force microscope. 
The first scanning acoustic microscope was developed in 1974 by R. A. Lemons and C. F. Quate at the Microwave Laboratory of Stanford University.
Since then, many improvements to such systems have been made to enhance resolution and accuracy. 
The scanning tunneling microscope, an instrument for imaging surfaces at the atomic level, was developed in 1981 by Gerd Binnig and Heinrich Rohrer at IBM Zurich Research Laboratory, for which they were awarded the Nobel Prize in Physics in 1986.
Binnig, Calvin Quate and Christoph Gerber invented the first atomic force microscope in 1986.
The first commercially available atomic force microscope was introduced in 1989.IBM researcher Don Eigler was the first to manipulate atoms using a scanning tunneling microscope in 1989.
He used 35 Xenon atoms to spell out the IBM logo.
He shared the 2010 Kavli Prize in Nanoscience for this work. 
In the early 1900s a significant alternative to light microscopy was developed, using electrons rather than light to generate the image.
Ernst Ruska started development of the first electron microscope in 1931 which was the transmission electron microscope (TEM).
The transmission electron microscope works on the same principle as an optical microscope but uses electrons in the place of light and electromagnets in the place of glass lenses.
Use of electrons instead of light allows a much higher resolution.
Development of the transmission electron microscope was quickly followed in 1935 by the development of the scanning electron microscope by Max Knoll.
Electron microscopes quickly became popular following the Second World War.
Ernst Ruska, working at Siemens developed the first commercial transmission electron microscope and major scientific conferences on electron microscopy started being held in the 1950s.
In 1965 the first commercial scanning electron microscope was developed by Professor Sir Charles Oatley and his postgraduate student Gary Stewart and marketed by the Cambridge Instrument Company as the "Stereoscan".
The most recent developments in light microscope largely centre on the rise of fluorescence microscopy in biology.
During the last decades of the 20th century, particularly in the post-genomic era, many techniques for fluorescent labeling of cellular structures were developed.
The main groups of techniques are small chemical staining of cellular structures, for example DAPI to label DNA, use of antibodies conjugated to fluorescent reporters, seeimmunofluorescence, and fluorescent proteins, such as green fluorescent protein.
These techniques use these different fluorophores for analysis of cell structure at a molecular level in both live and fixed samples.
The rise of fluorescence microscopy drove the development of a major modern microscope design, the confocal microscope.
The principle was patented in 1957 by Marvin Minsky, although laser technology limited practical application of the technique.
It was not until 1978 when Thomas and Christoph Cremer developed the first practical confocal laser scanning microscope and the technique rapidly gained popularity through the 1980s.
Much current research (in the early 21st century) on optical microscope techniques is focused on development of superresolution analysis of fluorescently labeled samples.
Structured illumination can improve resolution by around two to four times and techniques like stimulated Emission Depletion microscopy are approaching the resolution of electron microscopes.